Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance sheet assets:
Securities available-for-sale, at fair value	$ 541,079	$ 357,726
Carrying Amount
Balance sheet assets:
Cash and cash equivalents	500,309	670,528
Securities available-for-sale, at fair value	541,079	357,726
Loans, net	861,373	879,732
Accrued interest receivable	6,332	6,850
Total	1,909,093	1,914,836
Balance sheet liabilities:
Deposits	1,087,317	1,050,856
Accounts and drafts payable	905,479	835,386
Accrued interest payable	68	38
Total	1,992,864	1,886,280
Fair Value
Balance sheet assets:
Cash and cash equivalents	500,309	670,528
Securities available-for-sale, at fair value	541,079	357,726
Loans, net	861,828	883,461
Accrued interest receivable	6,332	6,850
Total	1,909,548	1,918,565
Balance sheet liabilities:
Deposits	1,087,317	1,050,856
Accounts and drafts payable	905,479	835,386
Accrued interest payable	68	38
Total	$ 1,992,864	$ 1,886,280