Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 61,625	$ 65,361
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	(6,740)	(2,125)
Net (gain) loss on disposal of property and equipment	(68)	(224)
Depreciation and amortization	12,168	12,293
Net premium amortization on investment securities	10,784	11,426
Net gains on investment securities transactions	(80)	(26)
Net gains on sales of mortgage loans held for sale	(12,947)	(20,376)
Net gain on sale of OREO	(551)	(3,195)
OREO valuation adjustments	87	3,180
Net impairment (reversal of impairment) of mortgage servicing rights	(117)	(121)
Deferred income tax expense	8,537	6,302
Net increase in cash surrender value of company-owned life insurance policies	(2,540)	28
Stock-based compensation expense	2,906	2,207
Tax benefits from stock-based compensation expense	1,541	1,578
Excess tax benefits from stock-based compensation	(1,503)	(1,488)
Originations of loans held for sale	(682,011)	(1,387,785)
Proceeds from sales of loans held for sale	676,061	1,419,539
Changes in operating assets and liabilities:
Increase in interest receivable	(2,749)	(1,515)
Decrease in other assets	(1,585)	9,434
Decrease in accrued interest payable	22	(1,135)
Decrease in accounts payable and accrued expenses	1,321	(2,622)
Net cash provided by operating activities	64,161	110,736
Cash flows from investing activities:
Purchases of held-to-maturity investment securities	(10,431)	(13,915)
Purchases of available-for-sale investment securities	(322,838)	(564,448)
Proceeds from maturities and paydowns of held-to-maturity investment securities	29,432	15,818
Proceeds from maturities and paydowns of available-for-sale investment securities	398,383	569,606
Purchases of company-owned life insurance	(15,000)	0
Proceeds from sales of mortgage servicing rights	266	470
Extensions of credit to customers, net of repayments	(148,854)	(147,826)
Recoveries of loans charged-off	7,323	9,434
Proceeds from sales of OREO	5,877	25,185
Acquisition of bank and bank holding company, net of cash and cash equivalents received	35,556	0
Capital expenditures, net of sales	(6,599)	(2,489)
Net cash used in investing activities	(26,885)	(108,165)
Cash flows from financing activities:
Net increase (decrease) in deposits	310,370	(131,786)
Net decrease in repurchase agreements	(25,880)	(77,675)
Net increase (decrease) in short-term borrowings	(11,926)	(22)
Repayments of long-term debt	(35)	(32)
Redemption of preferred stock	0	(50,000)
Proceeds from issuance of common stock	4,914	8,680
Excess tax benefits from stock-based compensation	1,503	1,488
Purchase and retirement of common stock	(9,736)	(448)
Dividends paid to common stockholders	(21,350)	(11,765)
Net cash provided by (used in) financing activities	247,860	(261,560)
Net increase (decrease) in cash and cash equivalents	285,136	(258,989)
Cash and cash equivalents at beginning of period	534,827	801,332
Cash and cash equivalents at end of period	819,963	542,343
Supplemental disclosures of cash flow information:
Cash paid during the period for income taxes	21,100	30,529
Cash paid during the period for interest expense	$ 13,049	$ 17,094