Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities:
Net income	$ 185,546	$ 149,467
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	27,900	43,850
Deferred tax (benefit) expense	(3,241)	14,425
Depreciation and amortization	28,060	27,342
Amortization of earning assets and funding, premiums/discounts, net	33,338	42,855
Stock-based compensation	9,050	8,558
Gain on sale, net of write-down, on foreclosed and repossessed assets	(551)	(744)
Write-down (gain on sale), net on premises and equipment	218	(713)
Impairment loss on investment 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	(10,943)	(11,060)
Mortgage banking activities	(8,038)	(11,335)
Proceeds from sale of loans held for sale	262,029	298,840
Origination of loans held for sale	(227,435)	(320,739)
Net decrease (increase) in derivative contract assets net of liabilities	11,235	(73,765)
Net (increase) decrease in accrued interest receivable and other assets	(19,405)	51,270
Net increase (decrease) in accrued expenses and other liabilities	12,386	(30,419)
Net cash provided by operating activities	300,275	187,567
Investing Activities:
Net decrease in interest-bearing deposits	2,469	133,969
Purchases of available for sale investment securities	(305,309)	(615,174)
Proceeds from maturities and principal payments of available for sale investment securities	695,595	430,099
Proceeds from sales of available for sale investment securities	0	259,283
Purchases of held-to-maturity investment securities	(887,240)	(640,218)
Proceeds from maturities and principal payments of held-to-maturity investment securities	525,499	517,513
Net proceeds of Federal Home Loan Bank stock	58,306	3,243
Alternative investments return of capital (capital call), net	107	(649)
Net increase in loans	(446,454)	(1,010,423)
Proceeds from loans not originated for sale	7,445	20,764
Proceeds from Life Insurance Policy	746	0
Proceeds from the sale of foreclosed and repossessed assets	5,651	6,900
Proceeds from the sale of premises and equipment	2,182	1,550
Additions to premises and equipment	(20,034)	(31,250)
Proceeds from redemption of other assets	7,581	0
Net cash used for investing activities	(353,456)	(924,393)
Financing Activities:
Net increase in deposits	1,551,987	1,248,710
Proceeds from Federal Home Loan Bank advances	9,245,000	14,150,000
Repayments of Federal Home Loan Bank advances	(10,580,218)	(14,226,147)
Net decrease in securities sold under agreements to repurchase and other borrowings	(46,624)	(350,695)
Dividends paid to common shareholders	(70,732)	(66,648)
Dividends paid to preferred shareholders	(6,072)	(6,072)
Exercise of stock options	5,301	2,372
Excess tax benefits from stock-based compensation	0	2,363
Common stock repurchase program	(11,585)	(11,206)
Common shares purchased related to stock compensation plan activity	(9,295)	(5,392)
Common stock warrants repurchased	0	(163)
Net cash (used for) provided by financing activities	77,762	737,122
Net decrease in cash and due from banks	24,581	296
Cash and due from banks at beginning of period	190,663	199,693
Cash and due from banks at end of period	215,244	199,989
Supplemental disclosure of cash flow information:
Interest paid	85,242	79,054
Income taxes paid	78,832	61,639
Noncash investing and financing activities:
Real Estate Owned, Transfer to Real Estate Owned	6,503	4,917
Transfer of loans from portfolio to loans-held-for-sale	$ 0	$ 20,547