Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net income	$ 199,204	$ 170,891	$ 159,649
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	88,797	60,503	43,949
Provision for credit losses	61,073	55,752	40,441
Deferred tax expense	128,983	15,250	550
Net securities gains	(5,916)	(712)	(822)
Tax benefit of stock-based compensation	(822)	(1,813)	(28)
Loans originated for sale	(1,097,869)	(713,087)	(445,558)
Loans sold	1,046,762	716,705	455,623
Net gain on sale of loans	(17,223)	(10,746)	(8,666)
Net change in:
Interest receivable	(18,143)	(5,214)	(4,688)
Interest payable	1,978	(150)	760
Bank owned life insurance	(11,200)	(5,373)	(6,397)
Other, net	(96,718)	10,702	(11,333)
Net cash flows provided by operating activities	278,906	292,708	223,480
Investing Activities
Net change in loans and leases	(1,100,481)	(816,093)	(985,999)
Securities available for sale:
Purchases	(1,141,620)	(1,066,361)	(421,901)
Sales	786,762	615,199	33,499
Maturities	569,949	543,923	284,483
Securities held to maturity:
Purchases	(1,185,859)	(1,063,273)	(465,597)
Sales	57,050	0	0
Maturities	394,823	357,111	277,967
Purchase of bank owned life insurance	(50,124)	(16,587)	(72,688)
Withdrawal/surrender of bank owned life insurance	0	0	72,664
Increase in premises and equipment	(56,874)	(59,327)	(9,723)
Net cash received in business combinations	196,964	245,762	144,629
Net cash flows used in investing activities	(1,529,410)	(1,259,646)	(1,142,666)
Financing Activities
Demand (non-interest-bearing and interest-bearing) and savings accounts	405,777	933,793	1,259,765
Time deposits	757,021	(119,734)	(166,283)
Short-term borrowings	379,139	251,713	7,238
Proceeds from issuance of long-term borrowings	155,399	46,357	134,953
Repayment of long-term borrowings	(199,318)	(173,477)	(34,968)
Net proceeds from issuance of common stock	11,181	18,472	12,731
Tax benefit of stock-based compensation	0	1,813	28
Cash dividends paid:
Preferred stock	(8,041)	(8,041)	(8,041)
Common stock	(142,618)	(101,670)	(84,511)
Net cash flows provided by financing activities	1,358,540	849,226	1,120,912
Net Increase (Decrease) in Cash and Cash Equivalents	108,036	(117,712)	201,726
Cash and cash equivalents at beginning of year	371,407	489,119	287,393
Cash and Cash Equivalents at End of Year	$ 479,443	$ 371,407	$ 489,119