Parent Corporation Only Financial Statements (Details) - Condensed Statements of Cash Flows - 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
Cash flows from operating activities:
Net income	$ 25,641	$ 24,786	$ 14,832	$ 6,030	$ 20,783	$ 21,696	$ 19,281	$ 11,635	$ 71,289	$ 73,395	$ 60,352
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on equity securities, net									(202)	(294)	267
Amortization of subordinated debt issuance costs									323	329	332
(Increase) decrease in other assets									(22,498)	(22,619)	(1,134)
(Decrease) increase in other liabilities									(4,174)	(2,785)	4,988
Net cash provided by operating activities									81,125	60,688	89,060
Cash flows from investing activities:
Sales of available-for-sale securities									19,624	183,728
Sales of equity securities										569
Net cash used in investing activities									(323,365)	(102,467)	(357,214)
Cash flows from financing activities:
Cash dividends on common stock									(14,317)	(12,160)	(9,664)
Repurchase of stock									(911)	(12,643)
Proceeds from exercise of stock options									233	360	875
Net cash provided by financing activities									344,513	70,896	290,938
Cash and cash equivalents at beginning of period				201,483				172,366	201,483	172,366	149,582
Cash and cash equivalents at end of period	303,756				201,483				303,756	201,483	172,366
Parent Company [Member]
Cash flows from operating activities:
Net income									71,289	73,395	60,352
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiary									(63,669)	(49,079)	(49,235)
Loss on equity securities, net										38	4
Amortization of subordinated debt issuance costs									323	329	332
(Increase) decrease in other assets									(50,001)		(959)
(Decrease) increase in other liabilities									(391)	(1,509)	3,843
Net cash provided by operating activities									(42,449)	23,174	14,337
Cash flows from investing activities:
Purchase of available-for-sale securities										(2)	(8)
Sales of available-for-sale securities										23
Sales of equity securities										569
Payment of short-term borrowing									(3,000)
Capital infusion to subsidiary											(64,500)
Net cash used in investing activities									(3,000)	590	(64,508)
Cash flows from financing activities:
Proceeds from subordinated debt									73,440		73,525
Cash dividends on common stock									(14,317)	(12,160)	(9,664)
Repurchase of stock									(911)	(12,643)
Proceeds from exercise of stock options									233	360	875
Net cash provided by financing activities									58,445	(24,443)	64,736
(Decrease) increase in cash and cash equivalents									12,996	(679)	14,565
Cash and cash equivalents at beginning of period				$ 21,392				$ 22,071	21,392	22,071	7,506
Cash and cash equivalents at end of period	$ 34,388				$ 21,392				$ 34,388	$ 21,392	$ 22,071