Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Activities
Net income per consolidated statements of income	$ 27,003	$ 29,148
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses, net	3,552	2,132
Depreciation and amortization	8,721	9,080
Net amortization of securities	2,087	2,050
Securities losses, net	310	0
Gains on sales of loans, net	(2,591)	(3,713)
Deferred income tax provision	125	4,625
Proceeds from sales of loans held for sale	238,007	236,732
Purchases and originations of loans held for sale	(267,422)	(275,587)
Originations of mortgage servicing rights	(3,072)	(3,126)
Increase in bank-owned life insurance	(1,226)	(1,179)
Net (increase) decrease in other assets	(3,511)	2,275
Net decrease in other liabilities	(7,185)	(9,839)
Other operating activities, net	7,078	4,554
Net cash provided by (used in) operating activities	1,876	(2,848)
Investing Activities
Proceeds from calls and maturities of securities held to maturity	72,168	24,372
Proceeds from calls and maturities of securities available for sale	99,722	91,776
Proceeds from sales of securities available for sale	24,693	0
Purchases of securities held to maturity	(50,031)	(6,738)
Purchases of securities available for sale	(113,654)	(112,367)
Net proceeds from bank-owned life insurance	604	0
Net decrease in federal funds sold and securities purchased under reverse repurchase agreements	250	1,885
Net decrease in member bank stock	8,280	14,100
Net (increase) decrease in loans	(153,989)	78,479
Purchases of premises and equipment	(2,814)	(2,790)
Proceeds from sales of premises and equipment	0	1,300
Proceeds from sales of other real estate	10,328	10,632
Purchases of software	(1,565)	0
Investments in tax credit and other partnerships	(46)	(38)
Net cash (used in) provided by investing activities	(106,054)	100,611
Financing Activities
Net increase in deposits	45,413	208,632
Net increase in federal funds purchased and securities sold under repurchase agreements	25,394	79,644
Net decrease in short-term borrowings	(65)	(350,051)
Payments on long-term FHLB advances	(30)	(30)
Common stock dividends	(15,640)	(15,639)
Common stock issued-net, long-term incentive plan	0	(830)
Excess tax expense from stock-based compensation arrangements	(147)	(218)
Net cash provided by (used in) financing activities	54,925	(78,492)
(Decrease) Increase in cash and cash equivalents	(49,253)	19,271
Cash and cash equivalents at beginning of period	277,751	315,973
Cash and cash equivalents at end of period	$ 228,498	$ 335,244