CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 261,428	$ 161,907	$ 168,146
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	27,554	24,845	24,431
Stock-based compensation	19,472	12,204	10,032
Provision for credit losses	32,501	9,942	11,869
Net amortization of premiums and accretion of discounts on securities and borrowings	38,454	46,346	24,310
Amortization of other intangible assets	18,416	10,016	11,327
Losses (gains) on securities transactions, net	2,342	20	(777)
Proceeds from sales of loans held for sale	687,983	813,855	572,439
Gains on sales of loans, net	(20,515)	(20,814)	(22,030)
Originations of loans held for sale	(406,087)	(444,290)	(425,713)
Losses (gains) on sales of assets, net	2,402	95	(1,358)
Net deferred income tax (benefit) expense	(11,780)	76,848	27,154
Net change in:
Fair value of borrowings hedged by derivative transactions	0	0	6,158
Cash surrender value of bank owned life insurance	(8,691)	(7,338)	(6,694)
Accrued interest receivable	(9,183)	(7,174)	(3,262)
Other assets	(33,145)	(57,353)	47,458
Accrued expenses and other liabilities	(7,562)	121	(24,313)
Net cash provided by operating activities	593,589	619,230	419,177
Cash flows from financing activities:
Net change in deposits	2,734,669	422,754	1,477,157
Net change in short-term borrowings	720,307	(332,332)	3,969
Proceeds from issuance of long-term borrowings, net	0	1,065,000	385,000
Repayments of long-term borrowings	(750,682)	(185,000)	(769,182)
Proceeds from issuance of preferred stock, net	0	98,101	0
Cash dividends paid to preferred shareholders	(15,859)	(6,277)	(7,188)
Cash dividends paid to common shareholders	(138,857)	(115,881)	(111,813)
Purchase of common shares to treasury	(3,801)	(2,645)	(3,191)
Common stock issued, net	2,704	8,207	112,085
Net cash provided by financing activities	2,548,481	951,927	1,086,837
Cash flows from investing activities:
Net loan originations and purchases	(3,257,939)	(1,418,073)	(1,379,431)
Investment securities held to maturity:
Purchases	(264,721)	(220,356)	(669,157)
Maturities, calls and principal repayments	241,077	290,929	325,766
Investment securities available for sale:
Purchases	(289,554)	(411,788)	(679,530)
Sales	44,377	2,727	4,782
Maturities, calls and principal repayments	255,031	204,684	867,998
Death benefit proceeds from bank owned life insurance	4,220	13,089	2,406
Proceeds from sales of real estate property and equipment	7,786	9,357	20,560
Purchases of real estate property and equipment	(26,440)	(18,117)	(20,707)
Cash and cash equivalents acquired in acquisitions	156,612	0	0
Net cash used in investing activities	(3,129,551)	(1,547,548)	(1,527,313)
Net change in cash and cash equivalents	12,519	23,609	(21,299)
Cash and cash equivalents at beginning of year	416,110	392,501	413,800
Cash and cash equivalents at end of year	428,629	416,110	392,501
Supplemental disclosures of cash flow information:
Interest on deposits and borrowings	290,444	170,614	151,209
Federal and state income taxes	53,587	29,013	26,564
Supplemental schedule of non-cash investing activities:
Transfer of loans to other real estate owned	743	7,301	8,089
Loans transferred to loans held for sale	289,633	313,201	174,501
Non-cash assets acquired:
Loans	3,736,984	0	0
Premises and equipment	62,066	0	0
Bank owned life insurance	49,052	0	0
Accrued interest receivable	12,123	0	0
Goodwill	394,028	0	0
Other intangible assets	45,906	0	0
Other assets	100,059	0	0
Total non-cash assets acquired	4,922,820	0	0
Liabilities assumed:
Deposits	3,564,843	0	0
Short-term borrowings	649,979	0	0
Long-term borrowings	87,283	0	0
Junior subordinated debentures issued to capital trusts	13,249	0	0
Accrued expenses and other liabilities	26,848	0	0
Total liabilities assumed	4,342,202	0	0
Net non-cash assets acquired	580,618	0	0
Net cash and cash equivalents acquired in acquisition	156,612	0	0
Common stock issued in acquisition	737,230	0	0
Held-to-maturity securities
Non-cash assets acquired:
Investment securities	214,217	0	0
Available-for-sale securities
Non-cash assets acquired:
Investment securities	$ 308,385	$ 0	$ 0