COMMITMENTS AND CONTINGENCIES: The Company has capital and other purchase commitments of approximately $565.1 million at September30, 2016 , primarily in connection with commitments for capital projects and client contract investments. At September30, 2016 , the Company also has letters of credit outstanding in the amount of $53.8 million . Certain of the Company's lease arrangements, primarily vehicle leases, with terms of one to eight years, contain provisions related to residual value guarantees. The maximum potential liability to the Company under such arrangements was approximately $127.8 million at September30, 2016 if the terminal fair value of vehicles coming off lease was zero . Consistent with past experience, management does not expect any significant payments will be required pursuant to these arrangements. No amounts have been accrued for guarantee arrangements at September30, 2016 . Rental expense for all operating leases was $180.7 million , $181.8 million and $188.0 million for fiscal 2016 , fiscal 2015 and fiscal 2014 , respectively. Following is a schedule of the future minimum rental and similar commitments under all noncancelable operating leases and certain residual value guarantees as of September30, 2016 (in thousands): 2017 $ 238,462 2018 92,589 2019 56,430 2020 56,835 2021 39,604 2022-Thereafter 229,209 Total minimum rental obligations $ 713,129 From time to time, the Company and its subsidiaries are a party to various legal actions, proceedings and investigations involving claims incidental to the conduct of their business, including actions by clients, consumers, employees, government entities and third parties, including under federal, state, international, national, provincial and local employment laws, wage and hour laws, discrimination laws, immigration laws, human health and safety laws, import and export controls and customs laws, environmental laws, false claims or whistleblower statutes, minority, women and disadvantaged business enterprise statutes, tax codes, antitrust an