Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating Activities:
Net income	$ 121,050	$ 97,650
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	17,750	29,600
Deferred tax expense	488	10,632
Depreciation and amortization	18,960	17,930
Amortization of earning assets and funding, premiums/discounts, net	23,287	27,449
Stock-based compensation	6,043	5,614
Gain on sale, net of write-down, on foreclosed and repossessed assets	(314)	(791)
Write-down (gain on sale), net on premises and equipment	559	(20)
Impairment loss on securities recognized in earnings	126	149
Gain on the sale of investment securities, net	0	(414)
Increase in cash surrender value of life insurance policies	7,223	7,317
Mortgage banking activities	(5,617)	(7,013)
Proceeds from sale of loans held for sale	173,338	170,572
Origination of loans held for sale	(147,437)	(182,329)
Net increase in derivative contract assets net of liabilities	(213)	(110,393)
Net (increase) decrease in accrued interest receivable and other assets	(24,054)	31,755
Net increase in accrued expenses and other liabilities	5,261	15,729
Net cash provided by operating activities	182,004	98,803
Investing Activities:
Net (increase) decrease in interest-bearing deposits	(4,201)	117,816
Purchases of available for sale securities	(106,476)	(428,991)
Proceeds from maturities and principal payments of available for sale securities	314,038	271,331
Proceeds from sales of available for sale securities	0	259,004
Purchases of held-to-maturity securities	(429,711)	(311,420)
Proceeds from maturities and principal payments of held-to-maturity securities	357,283	298,796
Net proceeds of Federal Home Loan Bank stock	39,141	3,243
Alternative investments return of capital (capital call), net	(296)	1,749
Net increase in loans	(263,241)	(640,922)
Proceeds from loans not originated for sale	7,445	11,743
Proceeds from Life Insurance Policy	484	0
Proceeds from the sale of foreclosed and repossessed assets	3,371	4,671
Proceeds from the sale of premises and equipment	507	750
Additions to premises and equipment	(13,392)	(20,639)
Proceeds from redemption of other assets	7,581	0
Net cash used for investing activities	(86,875)	(436,367)
Financing Activities:
Net increase in deposits	1,153,597	875,997
Proceeds from Federal Home Loan Bank advances	7,300,000	10,125,000
Repayments of Federal Home Loan Bank advances	(8,375,145)	(10,326,076)
Net decrease in securities sold under agreements to repurchase and other borrowings	(76,834)	(251,709)
Dividends paid to common shareholders	(46,862)	(43,791)
Dividends paid to preferred shareholders	(4,048)	(4,048)
Exercise of stock options	4,591	1,773
Excess tax benefits from stock-based compensation	0	2,241
Common stock repurchase program	0	(11,206)
Common shares purchased related to stock compensation plan activity	(9,283)	(5,183)
Common stock warrants repurchased	0	(163)
Net cash (used for) provided by financing activities	(53,984)	362,835
Net decrease in cash and due from banks	41,145	25,271
Cash and due from banks at beginning of period	190,663	199,693
Cash and due from banks at end of period	231,808	224,964
Supplemental disclosure of cash flow information:
Interest paid	53,354	51,527
Income taxes paid	53,334	43,093
Noncash investing and financing activities:
Real Estate Owned, Transfer to Real Estate Owned	3,167	3,285
Transfer of loans from portfolio to loans-held-for-sale	$ 0	$ 11,892