Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities
Net income per consolidated statements of income	$ 89,862	$ 79,488
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses, net	3,533	11,730
Depreciation and amortization	28,781	27,183
Net amortization of securities	8,084	6,833
Securities (gains) losses, net	(15)	310
Gains on sales of loans, net	(13,633)	(14,477)
Deferred income tax provision	4,800	12,900
Proceeds from sales of loans held for sale	885,520	1,030,784
Purchases and originations of loans held for sale	(895,992)	(1,096,979)
Originations of mortgage servicing rights	(11,630)	(12,392)
Earnings on bank-owned life insurance	(3,753)	(3,653)
Net change in other assets	29,599	(20,833)
Net change in other liabilities	4,205	5,405
Other operating activities, net	6,280	15,490
Net cash provided by operating activities	135,641	41,789
Investing Activities
Proceeds from maturities, prepayments and calls of securities held to maturity	128,515	221,002
Proceeds from maturities, prepayments and calls of securities available for sale	351,817	344,160
Proceeds from sales of securities available for sale	27,682	24,693
Purchases of securities held to maturity	(69,989)	(168,665)
Purchases of securities available for sale	(338,532)	(408,532)
Net proceeds from bank-owned life insurance	3,630	604
Net change in federal funds sold and securities purchased under reverse repurchase agreements	4,185	(250)
Net change in member bank stock	739	(2,153)
Net change in loans	(457,292)	(343,707)
Purchases of premises and equipment	(10,963)	(6,929)
Proceeds from sales of premises and equipment	7,792	435
Proceeds from sales of other real estate	20,301	37,378
Purchases of software	(3,492)	(5,072)
Investments in tax credit and other partnerships	(5,213)	(46)
Net cash used in business acquisition	(19,775)	0
Net cash used in investing activities	(360,595)	(307,082)
Financing Activities
Net change in deposits	9,572	97,471
Net change in federal funds purchased and securities sold under repurchase agreements	5,786	73,876
Net change in short-term borrowings	283,820	(1,057)
Payments on long-term FHLB advances	(49)	(78)
Proceeds from long-term FHLB advances	0	250,000
Redemption of junior subordinated debt securities	(3,000)	0
Common stock dividends	(47,099)	(46,983)
Repurchase and retirement of common stock	0	(750)
Shares withheld to pay taxes, long-term incentive plan	(1,659)	(992)
Net cash provided by financing activities	247,371	371,487
Net change in cash and cash equivalents	22,417	106,194
Cash and cash equivalents at beginning of period	327,706	277,751
Cash and cash equivalents at end of period	$ 350,123	$ 383,945