Consolidated Statements of Cash Flow - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 99,586	$ 134,879	$ 125,814
Adjustments to reconcile to net cash provided by operating activities:
Provision for credit losses	62,648	8,287	3,802
Depreciation and amortization	18,424	15,989	13,546
Net amortization of securities premiums and discounts	(94)	(4,282)	(421)
Realized securities losses (gains)	389	(812)	(47)
Gain on sales of loans	(6,067)	(3,619)	(2,902)
Cash receipts from the sale of loans originated for sale	415,589	238,324	187,461
Cash disbursements for loans originated for sale	(430,653)	(237,543)	(186,632)
Deferred income tax (benefit) provision	(9,491)	1,148	3,155
Gain on other assets	(2,345)	(1,372)	(596)
(Increase)/decrease in interest receivable	(325)	887	(3,390)
(Decrease)/increase in interest payable	(1,641)	(17)	1,179
Amortization of stock-based compensation arrangements	1,516	1,277	1,352
Excess tax benefit from stock-based compensation arrangements	(500)	(928)	(1,112)
Other, net	7,305	6,740	(1,199)
Net cash provided by operating activities	154,341	158,958	140,010
INVESTING ACTIVITIES
Net cash received from acquisitions, net of cash paid	18,397	77,672	6,248
Net decrease/(increase) in federal funds sold	1,000	(1,000)	23,548
Purchases of held for investment debt securities	(1,395)	(1,010)	(225)
Purchases of available for sale debt securities	(605,069)	(174,090)	(465,684)
Proceeds from maturities, calls and paydowns of held for investment debt securities	561	535	1,089
Proceeds from maturities, calls and paydowns of available for sale debt securities	547,729	508,293	126,909
Proceeds from sales of available for sale debt securities			31,285
Purchase of equity securities	(811)	(3,966)	(3,190)
Proceeds from paydowns and sales of equity securities	445	2,178	1,484
Net change in loans	(798,024)	(310,053)	49,354
Purchases of premises, equipment and computer software	(66,446)	(27,054)	(51,863)
Purchase of tax credits	(2,200)	(29,025)	(8,864)
Other, net	7,820	7,867	(3,890)
Net cash (used in) provided by investing activities	(897,993)	50,347	(293,799)
FINANCING ACTIVITIES
Net change in deposits	536,063	274,218	(139,510)
Net change in short-term borrowings		(575)	775
Proceeds from long-term borrowings	3,000
Paydown of long-term borrowings	(3,000)
Issuance of common stock in connection with stock options, net	1,790	2,484	2,238
Common stock acquired	(3,098)	(1,601)	(7,914)
Redemption of Junior Subordinated debentures			(5,155)
Cash dividends paid	(42,472)	(39,805)	(30,265)
Net cash provided by (used in) financing activities	492,283	234,721	(179,831)
Net (decrease)/increase in cash, due from banks and interest-bearing deposits	(251,369)	444,026	(333,620)
Cash, due from banks and interest-bearing deposits at the beginning of the period	1,868,281	1,424,255	1,757,875
Cash, due from banks and interest-bearing deposits at the end of the period	1,616,912	1,868,281	1,424,255
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	22,056	54,602	41,549
Cash paid during the period for income taxes	26,525	30,975	27,952
Noncash investing and financing activities:
Stock issued in acquisitions			39,498
Cash consideration for acquisitions	2,861	123,457	24,722
Fair value of assets acquired in acquisitions	47,838	729,378	377,320
Liabilities assumed in acquisitions	45,040	605,921	338,860
Unpaid common stock dividends declared	$ 11,125	$ 10,453	$ 9,826