Parent Company Financial Statements, Condensed Statements of Income and Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Expenses [Abstract]
Interest expense	$ 15,090	$ 25,450	$ 40,513
Other expenses	11,968	12,031	12,539
Income tax benefit	22,704	10,761	7,452
Net income	87,939	59,504	64,540
Unrealized holding gains (losses) on debt securities available-for-sale [Abstract]
Unrealized holding gains (losses) arising during the period	(24,827)	13,839	14,270
Less: Reclassification adjustments for realized gains included in net income	60	1,251	3
Other comprehensive income (loss), net of tax	(18,416)	9,315	10,864
Comprehensive income	69,523	68,819	75,404
Parent Company [Member]
Income [Abstract]
Dividends from subsidiaries	33,319	29,593	30,152
Other income	482	476	757
Total income	33,801	30,069	30,909
Expenses [Abstract]
Interest expense	1,090	1,519	2,520
Depreciation expense	70	112	144
Other expenses	5,878	3,302	3,273
Total expenses	7,038	4,933	5,937
Income before income taxes and equity in undistributed income of subsidiaries	26,763	25,136	24,972
Income tax benefit	(1,700)	(576)	(4,947)
Income before equity in undistributed income of subsidiaries	28,463	25,712	29,919
Equity in undistributed income of subsidiaries	59,476	33,792	34,621
Net income	87,939	59,504	64,540
Unrealized holding gains (losses) on debt securities available-for-sale [Abstract]
Unrealized holding gains (losses) arising during the period	(24,827)	13,839	14,270
Less: Reclassification adjustments for realized gains included in net income	60	1,251	3
Tax expense (benefit)	(6,471)	3,273	3,403
Other comprehensive income (loss), net of tax	(18,416)	9,315	10,864
Comprehensive income	$ 69,523	$ 68,819	$ 75,404