Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities
Net income	$ 159,649	$ 144,050	$ 117,804
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	43,949	40,119	30,768
Provision for credit losses	40,441	38,648	31,090
Deferred tax expense	550	44,113	15,291
Net securities gains	(822)	(11,717)	(808)
Other-than-temporary impairment losses on securities			27
Tax benefit of stock-based compensation	(28)	(2,714)	(1,326)
Loans originated for sale	(445,558)	(162,010)	(219,324)
Loans sold	455,623	168,533	243,782
Gain on sale of loans	(8,666)	(5,565)	(3,845)
Net change in:
Interest receivable	(4,688)	(2,211)	(1,675)
Interest payable	760	(875)	(2,173)
Securities classified as trading in business combination and sold		241,595	125,800
Bank owned life insurance	(6,397)	(10,401)	(3,598)
Other, net	(11,333)	(34,746)	14,280
Net cash flows provided by operating activities	223,480	446,819	346,093
Investing Activities
Net increase in loans and leases	(985,999)	(1,192,618)	(643,568)
Securities available for sale:
Purchases	(421,901)	(829,800)	(375,222)
Sales	33,499	175,872	22,047
Maturities	284,483	303,875	345,528
Securities held to maturity:
Purchases	(465,597)	(475,579)	(373,136)
Sales		4,570	17,428
Maturities	277,967	213,730	285,765
Purchase of bank owned life insurance	(72,688)	(16)	(10,016)
Withdrawal/surrender of bank owned life insurance	72,664	21,968
Increase in premises and equipment	(9,723)	(20,238)	(14,882)
Net cash received in business combinations	144,629	59,980	141,637
Net cash flows used in investing activities	(1,142,666)	(1,738,256)	(604,419)
Financing Activities
Demand (non-interest-bearing and interest-bearing) and savings accounts	1,259,765	652,808	458,153
Time deposits	(166,283)	(292,026)	(312,242)
Short-term borrowings	7,238	789,318	143,703
Increase of long-term borrowings	134,953	385,656	92,583
Repayment of long-term borrowings	(34,968)	(96,906)	(247,988)
Net proceeds from issuance of preferred stock			106,882
Net proceeds from issuance of common stock	12,731	12,857	62,092
Tax benefit of stock-based compensation	28	2,714	1,326
Cash dividends paid:
Preferred stock	(8,041)	(8,352)
Common stock	(84,511)	(81,220)	(71,246)
Net cash flows provided by financing activities	1,120,912	1,364,849	233,263
Net Increase (Decrease) in Cash and Cash Equivalents	201,726	73,412	(25,063)
Cash and cash equivalents at beginning of year	287,393	213,981	239,044
Cash and Cash Equivalents at End of Year	$ 489,119	$ 287,393	$ 213,981