CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Operating activities:
Net income	$ 68,220	$ 63,352
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	9,801	9,058
Amortization of intangible assets	3,293	3,408
Net accretion of premiums and discounts on securities and borrowings	(5,643)	(4,081)
Stock-based compensation	3,073	3,014
Provision for loan losses	4,647	4,807
Amortization of mortgage servicing rights	337	409
Income from bank-owned life insurance policies	(760)	(775)
Gain on sales of investment securities	0	(63,799)
Loss on debt extinguishments	0	63,500
Net (gain)/loss from sale of loans and other assets	(344)	248
Net change in loans held for sale	258	(913)
Change in other assets and liabilities	5,448	(6,297)
Net cash provided by operating activities	88,330	71,931
Investing activities:
Proceeds from sales of available-for-sale investment securities	0	711,540
Proceeds from maturities of available-for-sale investment securities	101,228	158,849
Proceeds from maturities of held-to-maturity investment securities	0	27,074
Proceeds from maturities of other investment securities	12	0
Proceeds from sale of other investment securities	0	7,229
Purchases of available-for-sale investment securities	(300,120)	(666,841)
Purchases of held-to-maturity investment securities	0	(5,298)
Purchases of other securities	(7,761)	(2)
Net increase in loans	(111,854)	(163,491)
Cash paid for acquisition, net of cash acquired of $0 and $0, respectively	(924)	0
Purchases of premises and equipment, net	(7,839)	(11,226)
Net cash (used in)/provided by investing activities	(327,258)	57,834
Financing activities:
Net increase in deposits	71,287	59,294
Net change in borrowings, net of payments of $8 and $565,145	201,892	(224,445)
Issuance of common stock	6,115	12,072
Cash dividends paid	(33,989)	(32,222)
Tax benefits from share-based payment arrangements	1,476	1,183
Net cash provided by/(used in) financing activities	246,781	(184,118)
Change in cash and cash equivalents	7,853	(54,353)
Cash and cash equivalents at beginning of period	149,647	228,558
Cash and cash equivalents at end of period	157,500	174,205
Supplemental disclosures of cash flow information:
Cash paid for interest	9,079	23,935
Cash paid for income taxes	19,527	19,328
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	12,255	11,279
Transfers from loans to other real estate	$ 2,111	$ 5,024