Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net income		$ 41,133	$ 49,418
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses		15,518	1,000
Depreciation, amortization and accretion, net		4,687	2,969
Deferred income tax benefit		(3,932)	(4,924)
Gain on sales of mortgage loans held for sale		(4,817)	(1,251)
Origination of mortgage loans held for sale		(201,099)	(69,983)
Proceeds from sale of mortgage loans held for sale		191,053	66,580
Bank owned life insurance income	[1]	(527)	(849)
(Gain)/loss on the disposal of premises and equipment		(176)	6
Income on other investments		0	(142)
Gain on the sale of other real estate owned		0	(63)
Stock compensation expense		2,636	2,732
Excess tax (benefit) expense from share-based compensation arrangements		(444)	(712)
Net change in accrued interest receivable and other assets		(20,224)	(7,296)
Net change in accrued interest payable and other liabilities		13,973	2,169
Net cash provided by operating activities		37,781	39,654
Investing activities:
Purchases of available for sale debt securities		(237,646)	(442,220)
Proceeds from sales of acquired available for sale debt securities		0	12,427
Proceeds from maturities and paydowns of available for sale debt securities		289,587	513,906
Proceeds from redemption of Federal Home Loan Bank stock		0	591
Proceeds from redemption of Federal Reserve Bank stock		0	490
Proceeds from redemption of interest bearing due from banks		0	1,761
Proceeds from the sale of held for investment loans		2,794	0
Net change in traditional loans		11,590	(142,108)
Purchases of premises and equipment		(4,068)	(4,179)
Proceeds from sale or disposal of premises and equipment		1,240	2,561
Proceeds from surrender of acquired bank owned life insurance		0	3,431
Proceeds from bank owned life insurance mortality benefit		0	909
Other investment activities		(860)	(2,766)
Proceeds from sales of other real estate owned		0	868
Cash for acquisition, net of cash acquired		0	(24,684)
Net cash used in investing activities		(579,419)	(79,013)
Financing activities:
Net change in deposits		620,521	26,342
Net change in securities sold under agreements to repurchase and federal funds purchased		6,827	(4,778)
Proceeds from Federal Home Loan Bank advances		90,000	90,000
Repayments of Federal Home Loan Bank advances		(113,564)	(99,620)
Repayment of acquired bank holding company line of credit		0	(2,300)
Redemption of acquired bank subordinated debentures		0	(3,609)
Repurchase of common stock		0	(9,164)
Share repurchases related to compensation plans		(2,487)	(2,768)
Cash dividends paid		(18,380)	(17,469)
Net cash provided by (used in) financing activities		582,917	(23,366)
Net change in cash and cash equivalents		41,279	(62,725)
Cash and cash equivalents at beginning of period		249,724	198,939
Cash and cash equivalents at end of period		291,003	136,214
Supplemental cash flow information:
Interest paid		10,178	17,519
Income taxes paid, net of refunds		9,608	9,281
Cash paid for operating lease liabilities		1,186	1,051
Supplemental non-cash activity:
Unfunded commitments in tax credit investments		9,667	3,424
Initial recognition of right-of-use lease assets		0	16,747
Initial recognition operating lease liabilities		0	18,067
Loans transferred to OREO		119	0
Fair value of assets acquired		0	204,613
Cash paid in acquisition		0	28,000
Liabilities assumed		0	176,613
Small Business Administration (SBA), CARES Act, Paycheck Protection Program [Member]
Investing activities:
Net change in PPP loans		$ (642,056)	$ 0

[1] Outside of the scope of ASC 606.