Parent Company Only Financial Information - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Net income	$ 7,899	$ 7,785	$ 8,246	$ 8,813	$ 10,484	$ 10,357	$ 9,767	$ 9,473	$ 32,743	$ 40,081	$ 33,719
Adjustments to reconcile net income to net cash provided by operating activities:
Net unrealized gains on trading securities									(328)	(1,888)	451
Decrease (increase) in other assets									(6,242)	1,072	(3,079)
Increase in other liabilities									(3,846)	3,610	4,613
Net Cash Provided By Operating Activities									28,758	52,042	44,855
Cash flows from investing activities
Net Cash Used In Investing Activities									(168,680)	(368,736)	(452,675)
Cash flows from financing activities:
Dividends paid on preferred stock									(1,147)	0	0
Purchase of treasury stock									(1,307)	(1,291)	(2,454)
Net proceeds from the issuance of preferred stock									57,785	0	0
Net proceeds from issuance of common stock									3,257	1,423	0
Net Cash Provided By Financing Activities									479,642	464,105	418,038
Net Increase in Cash and Cash Equivalents									339,720	147,411	10,218
Cash and Cash Equivalents, Beginning				192,974				45,563	192,974	45,563	35,345
Cash and Cash Equivalents, Ending	532,694				192,974				532,694	192,974	45,563
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net income									32,743	40,081	33,719
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed net income of bank subsidiary									(18,197)	(27,580)	(24,031)
(Equity in undistributed) distributions in excess of net income of non–bank subsidiaries									7,159	(3,914)	1,485
Net unrealized gains on trading securities									31	(24)	0
Decrease (increase) in other assets									21	177	872
Increase in other liabilities									1,091	1,267	1,089
Net Cash Provided By Operating Activities									22,848	10,007	13,134
Cash flows from investing activities
Purchase of trading securities									(2,000)	(36)	(44)
Investment in non-bank subsidiaries									0	0	(400)
Outlays for business acquisition									(16,126)	0	0
Investment in bank subsidiaries									(41,500)	0	0
Net Cash Used In Investing Activities									(59,626)	(36)	(444)
Cash flows from financing activities:
Dividends paid on common stock									(10,981)	(10,358)	(10,237)
Dividends paid on preferred stock									(1,147)	0	0
Purchase of treasury stock									(1,307)	(1,291)	(2,454)
Net proceeds from the issuance of preferred stock									57,785	0	0
Net proceeds from issuance of common stock									3,257	1,423	0
Net advance (to) from subsidiary									(850)	650	(1,200)
Net Cash Provided By Financing Activities									46,757	(9,576)	(13,891)
Net Increase in Cash and Cash Equivalents									9,979	395	(1,201)
Cash and Cash Equivalents, Beginning				$ 750				$ 355	750	355	1,556
Cash and Cash Equivalents, Ending	$ 10,729				$ 750				$ 10,729	$ 750	$ 355