Condensed Financial Statements of Parent Company, Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities [Abstract]
Net income	$ 66,336	$ 58,734	$ 56,036
Adjustments to reconcile net income to net cash provided by operating activities [Abstract]
Equity in undistributed net income of the Bank	(58,016)	(40,597)	(44,571)
Net cash provided by operating activities	59,963	58,119	80,858
Cash flows from investing activities [Abstract]
Net cash used in investing activities	(296,150)	(736,754)	(135,630)
Cash flows from financing activities [Abstract]
Common stock repurchases	0	(2,834)	0
Cash dividends paid	(12,075)	(11,700)	(11,221)
Net provided by financing activities	567,810	767,714	203,966
Net change in cash and cash equivalents	331,623	89,079	149,194
Cash and cash equivalents, beginning of year	383,837	294,758	145,564
Cash and cash equivalents, end of year	715,460	383,837	294,758
Parent Company [Member]
Cash flows from operating activities [Abstract]
Net income	66,336	58,734	56,036
Adjustments to reconcile net income to net cash provided by operating activities [Abstract]
Equity in undistributed net income of the Bank	(58,016)	(40,597)	(44,571)
Change in other assets and liabilities	739	(393)	62
Net cash provided by operating activities	9,059	17,744	11,527
Cash flows from investing activities [Abstract]
Payments for investments in non-qualified retirement plans	0	(403)	(6,273)
Net cash used in investing activities	0	(403)	(6,273)
Cash flows from financing activities [Abstract]
Common stock repurchases	0	(2,834)	0
Issuance of common stock	0	403	6,973
Cash dividends paid	(12,075)	(11,700)	(11,221)
Net provided by financing activities	(12,075)	(14,131)	(4,248)
Net change in cash and cash equivalents	(3,016)	3,210	1,006
Cash and cash equivalents, beginning of year	4,551	1,341	335
Cash and cash equivalents, end of year	$ 1,535	$ 4,551	$ 1,341