Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income		$ 50,056	$ 41,133
Purchases of available for sale debt securities		(325,073)	(237,646)
Proceeds from sales of acquired available for sale debt securities		91,094	0
Proceeds from maturities and paydowns of available for sale debt securities		131,936	289,587
Proceeds from redemption of Federal Home Loan Bank stock		8,980	0
Proceeds from the sale of held for investment loans		0	2,794
Net change in non-PPP loans		(232,636)	11,590
Purchases of premises and equipment		(3,243)	(4,068)
Proceeds from sale or disposal of premises and equipment		0	1,240
Other investment activities		(3,975)	(860)
Proceeds from sales of other real estate owned		919	0
Cash from acquisition, net of cash paid		24,981	0
Net cash provided by (used in) investing activities		11,834	(579,419)
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses		1,147	17,918
Depreciation, amortization and accretion, net		7,925	4,687
Deferred income tax expense (benefit)		3,837	(3,932)
Gain on sale of mortgage loans held for sale		(2,708)	(4,817)
Origination of mortgage loans held for sale		(169,542)	(201,099)
Proceeds from sale of mortgage loans held for sale		187,667	191,053
Bank owned life insurance income	[1]	(642)	(527)
(Gain)/loss on the disposal of premises and equipment		41	(176)
Gain on the sale of other real estate owned		(180)	0
Stock compensation expense		3,428	2,636
Excess tax benefit from share-based compensation arrangements		(1,152)	(444)
Net change in accrued interest receivable and other assets		1,656	(20,224)
Net change in accrued interest payable and other liabilities		(18,401)	11,573
Net cash provided by operating activities		63,132	37,781
Cash flows from financing activities:
Net change in deposits		314,218	620,521
Net change in securities sold under agreements to repurchase and federal funds purchased		14,511	6,827
Proceeds from Federal Home Loan Bank advances		30,000	90,000
Repayments of Federal Home Loan Bank advances		(142,745)	(113,564)
Share repurchases related to compensation plans		(3,177)	(2,487)
Cash dividends paid		(20,777)	(18,380)
Net cash provided by financing activities		192,030	582,917
Net change in cash and cash equivalents		266,996	41,279
Beginning cash and cash equivalents		317,945	249,724
Ending cash and cash equivalents		584,941	291,003
Interest paid		4,669	10,178
Income taxes paid, net of refunds		13,359	9,608
Cash paid for operating lease liabilities		1,898	1,186
Supplemental non-cash activity:
Unfunded commitments in tax credit investments		6,307	9,667
Due to broker		3,590	0
Dividends payable		194	189
Loans transferred to OREO		7,106	119
Fair value of assets acquired		1,389,327
Consideration paid in acquisition		28,276
Common stock issued in acquisition		204,670
Total consideration paid		232,946
Liabilities assumed		1,156,381
Small Business Administration (SBA), CARES Act, Paycheck Protection Program [Member]
Cash flows from operating activities:
Net change in PPP loans		$ 318,851	$ (642,056)

[1] Outside of the scope of ASC 606.