Statements of Cash Flows - Cash Flows Supplementary Disclosures (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Statement of cash flows specific transaction amounts [Abstract]
Income taxes paid	$ 14,825	$ 36,211
Interest expense paid on deposits and borrowings	19,354	35,246
Noncash transfers from loans to other real estate	770	496
Finance right-of-use assets resulting from lease liabilities	92
Operating right-of-use assets resulting from lease liabilities	$ 6,833	2,368
Transfer of long-term FHLB advances to short-term		$ 651