Commitments and Contingencies (a) Off-Balance Sheet Financial Instruments In the normal course of business, the Company enters into various transactions, which, in accordance with GAAP, are not included in its consolidated balance sheets. The Company enters into these transactions to meet the financing needs of its customers. These transactions include commitments to extend credit and standby letters of credit, which involve, to varying degrees, elements of credit risk and interest rate risk in excess of the amounts recognized in the consolidated balance sheets. The Company minimizes its exposure to losses under these commitments by subjecting them to credit approval and monitoring procedures. The Company enters into contractual commitments to extend credit, normally with fixed expiration dates or termination clauses, at specified rates and for specific purposes. Substantially all of the Companys commitments to extend credit are contingent upon customers maintaining specific credit standards at the time of loan funding. Standby letters of credit are written conditional commitments issued by the Company to guarantee the performance of a customer to a third-party. In the event the customer does not perform in accordance with the terms of the agreement with the third-party, the Company would be required to fund the commitment. The maximum potential amount of future payments the Company could be required to make is represented by the contractual amount of the commitment. If the commitment were funded, the Company would be entitled to seek recovery from the customer. Based on the Companys credit risk exposure assessment of its standby letter of credit arrangements, the arrangements contain security and debt covenants similar to those contained in loan agreements. The contractual or notional amounts of these instruments, which reflect the extent of the Companys involvement in particular classes of off-balance sheet financial instruments, are summarized as follows: September 30, December 31, 2018 2017 Loan origination commitments $ 372,047 $ 510,135 Unused lines of credit 1,359,953 1,195,656 Letters of credit 289,877 166,824 (b) Lease Commitments The Company leases certain premises and equipment under operating leases with terms expiring through January 2034. Included in occupancy and office operations expense was net rent expense of $4,572 and $1,874 during the three months ended September 30, 2018 and 2017 , respectively. Net rent expense was $13,972 and $6,263 for the nine months ended September 30, 2018 and 2017 , respectively. Future minimum lease payments due under non-cancelable operating leases at September 30, 2018 were as follows: Remainder of 2018 $ 4,863 2019 17,817 2020 16,577 2021 13,878 2022 10,007 2023 8,163 2024 and thereafter 22,158 $ 93,463 (c) Litigation The Company and the Bank are involved in a number of judicial proceedings concerning matters arising from their business activities. These include routine legal proceedings arising in the ordinary course of business. These proceedings also include actions brought against the Company and the Bank with respect to corporate matters and transactions in which the Company and the Bank are or were involved. There can be no assurance as to the ultimate outcome of a legal proceeding; however, the Company and the Bank have generally denied liability in all significant litigation pending against them and intend to defend vigorously each case, other than matters that are determined appropriate to be settled. The Company and the Bank accrue a liability for legal claims when payments associated with the claims become probable and the costs can be reasonably estimated. The actual costs of resolving legal claims may be substantially higher or lower than the amounts accrued for those claims.