Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities
Net income per consolidated statements of income	$ 79,488	$ 88,180
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses, net	11,730	7,760
Depreciation and amortization	27,183	27,995
Net amortization of securities	6,833	6,411
Securities losses, net	310	0
Gains on sales of loans, net	(14,477)	(13,301)
Deferred income tax provision	12,900	11,600
Proceeds from sales of loans held for sale	1,030,784	943,804
Purchases and originations of loans held for sale	(1,096,979)	(985,935)
Originations of mortgage servicing rights	(12,392)	(13,321)
Increase in bank-owned life insurance	(3,653)	(3,598)
Net (increase) decrease in other assets	(20,833)	18,480
Net increase (decrease) in other liabilities	5,405	(1,151)
Other operating activities, net	14,617	6,325
Net cash provided by operating activities	40,916	93,249
Investing Activities
Proceeds from calls and maturities of securities held to maturity	221,002	95,467
Proceeds from calls and maturities of securities available for sale	344,160	345,156
Proceeds from sales of securities available for sale	24,693	0
Purchases of securities held to maturity	(168,665)	(68,715)
Purchases of securities available for sale	(408,532)	(375,866)
Net proceeds from bank-owned life insurance	604	655
Net (increase) decrease in federal funds sold and securities purchased under reverse repurchase agreements	(250)	1,885
Net increase in member bank stock	(2,153)	(12,585)
Net increase in loans	(343,707)	(247,772)
Purchases of premises and equipment	(6,929)	(9,934)
Proceeds from sales of premises and equipment	435	2,896
Proceeds from sales of other real estate	37,378	33,809
Purchases of software	(5,072)	(6,576)
Investments in tax credit and other partnerships	(46)	(315)
Purchase of insurance book of business	0	(2,787)
Net cash used in investing activities	(307,082)	(244,682)
Financing Activities
Net increase (decrease) in deposits	97,471	(285,954)
Net increase in federal funds purchased and securities sold under repurchase agreements	73,876	90,661
Net (decrease) increase in short-term borrowings	(1,057)	298,888
Payments on long-term FHLB advances	(78)	(77)
Proceeds from long-term FHLB advances	250,000	0
Common stock dividends	(46,983)	(46,952)
Common stock issued-net, long-term incentive plan	0	(842)
Repurchase and retirement of common stock	(750)	0
Excess tax expense from stock-based compensation arrangements	(119)	(212)
Net cash provided by financing activities	372,360	55,512
Increase (Decrease) in cash and cash equivalents	106,194	(95,921)
Cash and cash equivalents at beginning of period	277,751	315,973
Cash and cash equivalents at end of period	$ 383,945	$ 220,052