16. Segment Reporting As of December 31, 2018, we had two reportable segments (Education and Trade Publishing). Our Education segment provides educational products, technology platforms and services to meet the diverse needs of todays classrooms. These products and services include print and digital content in the form of textbooks, digital courseware, instructional aids, educational assessment and intervention solutions, which are aimed at improving achievement and supporting learning for students who are not keeping pace with peers, professional development and school reform services. Our Trade Publishing segment primarily develops, markets and sells consumer books in print and digital formats and licenses book rights to other publishers and electronic businesses in the United States and abroad. The principal distribution channels for Trade Publishing products are retail stores, both physical and online, and wholesalers. We measure and evaluate our reportable segments based on net sales and segment Adjusted EBITDA from continuing operations. We exclude from our segments certain corporate-related expenses, as our corporate functions do not meet the definition of a segment, as defined in the accounting guidance relating to segment reporting. In addition, certain transactions or adjustments that our Chief Operating Decision Maker considers to be non-operational, such as amounts related to goodwill and other intangible asset impairment charges, derivative instruments charges, acquisition/disposition-related activity, restructuring/integration costs, severance, separation costs and facility closures, equity compensation charges, legal settlement charges, gains or losses from divestitures, amortization and depreciation expenses, as well as interest and taxes, are excluded from segment Adjusted EBITDA from continuing operations. Although we exclude these amounts from segment Adjusted EBITDA from continuing operations, they are included in reported consolidated net loss and are included in the reconciliation below. As a result of the sale of the Riverside Business, the results of the Riverside Business are no longer presented within continuing operations. Accordingly, the segment disclosures for the Education reportable segment has been recast for all periods to exclude the results of the Riverside Business. These changes had no impact on the previously reported financial results for the Trade reportable segment. (in thousands) Year Ended December 31, Education Trade Publishing Corporate/ Other 2018 Net sales $ 1,122,689 $ 199,728 $  Segment Adjusted EBITDA 210,604 21,942 (40,418 ) 2017 Net sales $ 1,146,453 $ 180,576 $  Segment Adjusted EBITDA 223,941 12,096 (50,758 ) 2016 Net sales $ 1,126,363 $ 165,615 $  Segment Adjusted EBITDA 194,632 6,255 (48,582 ) The following table disaggregates our net sales by major source: Year Ended December 31, 2018 (in thousands) Education Trade Publishing Consolidated Core solutions (1) $ 538,166 $  $ 538,166 Extensions businesses (2) 584,523  584,523 Trade products  199,728 199,728 Net sales $ 1,122,689 $ 199,728 $ 1,322,417 Year Ended December 31, 2017 (in thousands) Education Trade Publishing Consolidated Core solutions (1) $ 595,097 $  $ 595,097 Extensions businesses (2) 551,356  551,356 Trade products  180,576 180,576 Net sales $ 1,146,453 $ 180,576 $ 1,327,029 Year Ended December 31, 2016 (in thousands) Education Trade Publishing Consolidated Core solutions (1) $ 602,862 $  $ 602,862 Extensions businesses (2) 523,501  523,501 Trade products  165,615 165,615 Net sales $ 1,126,363 $ 165,615 $ 1,291,978 (1) Comprehensive solutions primarily for reading, math, science and social studies programs. (2) Primarily consists of our Heinemann brand, intervention, supplemental and professional services. Reconciliation of Segment Adjusted EBITDA to the consolidated statements of operations is as follows: (in thousands) Years Ended December 31, 2018 2017 2016 Total Segment Adjusted EBITDA $ 192,128 $ 185,279 $ 152,305 Interest expense (45,680 ) (42,805 ) (39,181 ) Interest income 2,550 1,338 518 Depreciation expense (75,116 ) (71,049 ) (74,467 ) Amortization expensefilm asset (6,057 )   Amortization expense (170,903 ) (195,394 ) (209,592 ) Non-cash chargesstock compensation (13,248 ) (10,728 ) (10,491 ) Non-cash chargesloss on derivative instruments (1,374 ) 1,366 (614 ) Non-cash chargesasset impairment charges  (3,980 ) (130,205 ) Purchase accounting adjustments   (5,116 ) Fees, expenses or charges for equity offerings, debt or acquisitions/dispositions (2,883 ) (1,464 ) (1,123 ) 2017 Restructuring Plan (4,657 ) (37,775 )  Restructuring/Integration   (14,364 ) Severance, separation costs and facility closures (6,821 ) (177 ) (15,371 ) Legal reimbursement (settlement)  3,633 (10,000 ) Gain on sale of assets 201   Loss before taxes (131,860 ) (171,756 ) (357,701 ) (Provision) benefit for income taxes (5,597 ) 51,419 51,556 Net loss from continuing operations $ (137,457 ) $ (120,337 ) $ (306,145 ) Segment information as of December 31, 2018 and 2017 is as follows: (in thousands) 2018 2017 Total assetsEducation segment $ 1,999,481 $ 2,121,647 Total assetsTrade Publishing segment 167,510 173,395 Total assetsCorporate and Other 328,133 268,549 Total consolidated assets $ 2,495,124 $ 2,563,591 The following represents long-lived assets (property, plant, and equipment) outside of the United States, which are substantially in Ireland. All other long-lived assets are located in the United States. (in thousands) 2018 2017 Long-lived assetsInternational $ 64 $ 7,593 The following is a schedule of net sales by geographic region: (in thousands) Year Ended December 31, 2018 Net salesU.S. $ 1,249,568 Net salesInternational 72,849 Total net sales $ 1,322,417 Year Ended December 31, 2017 Net salesU.S. $ 1,254,956 Net salesInternational 72,073 Total net sales $ 1,327,029 Year Ended December 31, 2016 Net salesU.S. $ 1,203,855 Net salesInternational 88,123 Total net sales $ 1,291,978