Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows From Operating Activities
Net income	$ 57,829,000	$ 71,163,000
Reconciliation of net income to net cash provided by operating activities:
Provision for loan losses	31,008,000	(913,000)
Net security premium amortization	2,832,000	1,827,000
Loan discount accretion	(4,789,000)	(4,473,000)
Other purchase accounting accretion and amortization, net	55,000	(16,000)
Foreclosed property losses and write-downs, net	284,000	899,000
Gains on securities available for sale	(8,024,000)	(97,000)
Other losses	157,000	331,000
Increase (decrease) in net deferred loan costs	7,380,000	(261,000)
Depreciation of premises and equipment	4,392,000	4,326,000
Amortization of operating lease right-of-use assets	1,522,000	1,372,000
Repayments of lease obligations	(1,392,000)	(1,250,000)
Stock-based compensation expense	2,013,000	1,748,000
Amortization of intangible assets	2,961,000	3,737,000
Amortization of SBA servicing assets	1,231,000	975,000
Fees/gains from sale of presold mortgages and SBA loans	(15,266,000)	(9,725,000)
Origination of presold mortgage loans in process of settlement	(294,270,000)	(108,723,000)
Proceeds from sales of presold mortgage loans in process of settlement	290,657,000	99,606,000
Origination of SBA loans for sale	(117,412,000)	(125,982,000)
Proceeds from sales of SBA loans	82,998,000	101,349,000
Increase in accrued interest receivable	(2,998,000)	(293,000)
Increase in other assets	(7,454,000)	(4,061,000)
(Decrease) increase in accrued interest payable	(849,000)	193,000
Increase in other liabilities	1,180,000	1,690,000
Net cash provided by operating activities	34,045,000	33,422,000
Cash Flows From Investing Activities
Purchases of securities available for sale	(701,201,000)	(339,030,000)
Purchases of securities held to maturity	(69,899,000)	0
Proceeds from maturities/issuer calls of securities available for sale	156,108,000	114,003,000
Proceeds from maturities/issuer calls of securities held to maturity	26,989,000	26,316,000
Proceeds from sales of securities available for sale	219,697,000	39,797,000
Redemptions of FRB and FHLB stock, net	9,853,000	4,088,000
Net increase in loans	(327,496,000)	(116,664,000)
Proceeds from sales of foreclosed properties	1,880,000	4,628,000
Purchases of premises and equipment	(8,983,000)	(2,714,000)
Proceeds from sales of premises and equipment	189,000	1,148,000
Net cash paid in acquisition	(9,559,000)	0
Net cash used by investing activities	(702,422,000)	(268,428,000)
Cash Flows From Financing Activities
Net increase in deposits	1,128,951,000	216,195,000
Net decrease in short-term borrowings	(148,000,000)	(55,000,000)
Proceeds from long-term borrowings	150,000,000	0
Payments on long-term borrowings	(252,003,000)	(51,089,000)
Cash dividends paid – common stock	(15,798,000)	(10,108,000)
Repurchases of common stock	(28,701,000)	(10,000,000)
Proceeds from stock option exercises	0	129,000
Payment of taxes related to stock withheld	(178,000)	(558,000)
Net cash provided by financing activities	834,271,000	89,569,000
Increase (decrease) in cash and cash equivalents	165,894,000	(145,437,000)
Cash and cash equivalents, beginning of period	231,302,000	462,898,000
Cash and cash equivalents, end of period	397,196,000	317,461,000
Supplemental Disclosures of Cash Flow Information:
Cash paid during the period for interest	17,094,000	25,397,000
Cash paid during the period for income taxes	21,302,000	20,106,000
Non-cash: Unrealized gain (loss) on securities available for sale, net of taxes	18,143,000	15,137,000
Non-cash: Foreclosed loans transferred to other real estate	1,032,000	2,676,000
Non-cash: Initial recognition of operating lease right-of-use assets and operating lease liabilities	253,000	19,406,000
Non-cash: Equity issued related to acquisitions	494,000	3,070,000
Non-cash: Loans acquired	14,633,000	0
Non-cash: Other assets acquired	451,000	0
Non-cash: Borrowings assumed	$ 11,671,000	$ 0