Consolidated Statements of Cash Flow $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 134,879	$ 125,814	$ 86,439
Adjustments to reconcile to net cash provided by operating activities:
Provision for loan losses	8,287	3,802	8,512
Depreciation and amortization	15,989	13,546	11,791
Net amortization of securities premiums and discounts	(4,282)	(421)	(148)
Realized securities gains	(812)	(47)	(4,060)
Gain on sales of loans	(3,619)	(2,902)	(2,921)
Cash receipts from the sale of loans originated for sale	238,324	187,461	211,569
Cash disbursements for loans originated for sale	(237,543)	(186,632)	(205,574)
Deferred income tax provision	1,148	3,155	4,383
(Gain)/loss on other assets	(1,372)	(596)	46
Decrease/(increase) in interest receivable	887	(3,390)	(3,284)
(Decrease)/increase in interest payable	(17)	1,179	366
Amortization of stock-based compensation arrangements	1,277	1,352	1,180
Excess tax benefit from stock-based compensation arrangements	(928)	(1,112)	(2,601)
Other, net	6,740	(1,199)	4,051
Net cash provided by operating activities	158,958	140,010	109,749
INVESTING ACTIVITIES
Net cash received from acquisitions, net of cash paid	77,672	6,248
Net (increase)/decrease in federal funds sold	(1,000)	23,548
Purchases of held for investment securities	(1,010)	(225)	(220)
Purchases of available for sale securities	(174,090)	(465,684)	(84,109)
Proceeds from maturities, calls and paydowns of held for investment securities	535	1,089	2,293
Proceeds from maturities, calls and paydowns of available for sale securities	508,293	126,909	78,682
Proceeds from sales of available for sale securities		31,285
Purchase of equity securities	(3,966)	(3,190)	(1,668)
Proceeds from paydowns and sales of equity securities	2,178	1,484	5,793
Net change in loans	(310,053)	49,354	(331,362)
Purchases of premises, equipment and computer software	(27,054)	(51,863)	(18,007)
Purchase of tax credits	(29,025)	(8,864)	(5,224)
Other, net	7,867	(3,890)	4,038
Net cash provided by (used in) investing activities	50,347	(293,799)	(349,784)
FINANCING ACTIVITIES
Net change in deposits	274,218	(139,510)	166,988
Net change in short-term borrowings	(575)	775	400
Issuance of common stock in connection with stock options, net	2,484	2,238	4,844
Common stock acquired	(1,601)	(7,914)
Redemption of Junior Subordinated debentures		(5,155)
Cash dividends paid	(39,805)	(30,265)	(24,783)
Net cash provided by (used in) financing activities	234,721	(179,831)	147,449
Net increase/(decrease) in cash, due from banks and interest-bearing deposits	444,026	(333,620)	(92,586)
Cash, due from banks and interest-bearing deposits at the beginning of the period	1,424,255	1,757,875	1,850,461
Cash, due from banks and interest-bearing deposits at the end of the period	1,868,281	1,424,255	1,757,875
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	54,602	41,549	20,563
Cash paid during the period for income taxes	30,975	27,952	41,058
Noncash investing and financing activities:
Stock issued in acquisitions		39,498
Cash consideration for acquisitions	123,457	24,722
Fair value of assets acquired in acquisitions	729,378	377,320
Liabilities assumed in acquisitions	605,921	338,860
Unpaid common stock dividends declared	$ 10,453	$ 9,826	$ 6,693