Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities:
Net income	$ 156,749	$ 151,398	$ 137,210
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	32,942	20,537	46,033
Depreciation and amortization	36,671	32,117	26,180
Deferred income tax expense	23,054	4,125	1,539
Stock-based compensation expense	9,656	7,754	6,799
Excess tax benefits from stock-based compensation arrangements	(744)	(444)	(474)
Net amortization of premium on securities	3,398	1,498	2,934
Accretion of discounts on loans	(34,378)	(42,539)	(34,273)
Mortgage servicing rights fair value change, net	(213)	1,428	(1,739)
Originations and purchases of mortgage loans held-for-sale	(3,903,777)	(3,182,684)	(3,708,364)
Proceeds from sales of mortgage loans held-for-sale	3,971,724	3,241,489	3,862,030
Bank owned life insurance income, net of claims	(3,146)	(2,701)	(3,446)
Decrease (increase) in trading securities, net	758	(709)	86
Net (increase) decrease in brokerage customer receivables	(3,410)	6,732	(6,089)
Gains on mortgage loans sold	(104,695)	(75,768)	(75,793)
(Gains) losses on available-for-sale securities, net	(323)	504	3,000
Loss on sales of premises and equipment, net	807	644	23
Net (gains) losses on sales and fair value adjustments of other real estate owned	(350)	3,735	136
(Increase) decrease in accrued interest receivable and other assets, net	(147,063)	77,409	53,166
Decrease in accrued interest payable and other liabilities, net	292	(38,902)	(21,749)
Net Cash Provided by Operating Activities	37,952	205,623	287,209
Investing Activities:
Proceeds from maturities of available-for-sale securities	506,798	431,347	295,807
Proceeds from maturities of held-to-maturity securities	55	0	0
Proceeds from sales of available-for-sale securities	1,515,559	852,330	138,274
Proceeds from calls of held-to-maturity securities	770	0	0
Purchases of available-for-sale securities	(2,092,652)	(1,597,587)	(489,131)
Purchases of held-to-maturity securities	(22,892)	0	0
(Purchase) redemption of Federal Home Loan Bank and Federal Reserve Bank stock, net	(9,999)	(12,321)	303
Net cash (paid) received for acquisitions	(15,428)	228,946	(14,491)
Divestiture of operations	0	0	(149,100)
Proceeds from sales of other real estate owned	50,405	92,620	100,162
Proceeds received from the FDIC related to reimbursements on covered assets	1,859	19,999	53,443
Net decrease (increase) in interest-bearing deposits with banks	531,396	(502,863)	643,626
Net increase in loans	(2,066,666)	(1,311,927)	(747,420)
Redemption of bank owned life insurance	2,701	0	0
Purchases of premises and equipment, net	(43,459)	(38,136)	(37,694)
Net Cash Used for Investing Activities	(1,641,553)	(1,837,592)	(206,221)
Financing Activities:
Increase (decrease) in deposit accounts	1,381,425	1,217,396	(78,946)
Increase (decrease) in other borrowings, net	44,685	(58,639)	(22,396)
Increase (decrease) in Federal Home Loan Bank advances, net	115,186	315,550	(18,000)
Proceeds from issuance of subordinated notes, net	0	139,090	0
Repayment of subordinated notes	0	0	(15,000)
Excess tax benefits from stock-based compensation arrangements	744	444	474
Net proceeds from issuance of Series D preferred stock	120,842	0	0
Issuance of common shares resulting from exercise of stock options, employee stock purchase plan and conversion of common stock warrants	16,119	10,453	19,113
Common stock repurchases	(424)	(549)	(3,504)
Dividends paid	(29,888)	(24,933)	(13,893)
Net Cash Provided by (Used for) Financing Activities	1,648,689	1,598,812	(132,152)
Net Increase (Decrease) in Cash and Cash Equivalents	45,088	(33,157)	(51,164)
Cash and Cash Equivalents at Beginning of Period	230,707	263,864	315,028
Cash and Cash Equivalents at End of Period	275,795	230,707	263,864
Cash paid during the year for:
Interest	77,737	73,334	83,395
Income taxes, net	94,723	72,575	97,703
Acquisitions:
Fair value of assets acquired, including cash and cash equivalents	1,187,115	475,398	559,694
Value ascribed to goodwill and other intangible assets	79,879	37,526	35,056
Fair value of liabilities assumed	1,033,219	405,801	511,603
Non-cash activities
Transfer of available-for-sale securities to held-to-maturity securities	862,712	0	0
Transfer to other real estate owned from loans	28,565	52,102	81,526
Common stock issued for acquisitions	$ 38,723	$ 0	$ 23,070