CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Net income	$ 63,352	$ 58,264
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	9,058	8,487
Amortization of intangible assets	3,408	3,343
Net accretion of premiums and discounts on securities and borrowings	(4,081)	(4,167)
Stock-based compensation	3,014	2,855
Provision for loan losses	4,807	6,442
Amortization of mortgage servicing rights	409	536
Income from bank-owned life insurance policies	(775)	(833)
Gain on sales of investment securities	(63,799)	(291)
Loss on debt extinguishments	63,500	0
Net loss/(gain) from sale of loans and other assets	248	229
Net change in loans held for sale	(913)	488
Change in other assets and liabilities	(6,297)	12,815
Net cash provided by operating activities	71,931	88,168
Investing activities:
Proceeds from sales of available-for-sale investment securities	711,540	5,378
Proceeds from maturities of available-for-sale investment securities	158,849	144,958
Proceeds from maturities of held-to-maturity investment securities	27,074	20,517
Proceeds from sale of other investment securities	7,229	275
Purchases of available-for-sale investment securities	(666,841)	(745,074)
Purchases of held-to-maturity investment securities	(5,298)	(107,317)
Purchases of other securities	(2)	(14)
Net increase in loans	(163,491)	(187,154)
Cash received from acquisition, net of cash paid of $0 and $0	0	600,972
Purchases of premises and equipment, net	(11,226)	(7,103)
Net cash provided by (used in) investing activities	57,834	(274,562)
Financing activities:
Net increase in deposits	59,294	115,422
Net change in borrowings, net of payments of $565,145 and $165	(224,445)	(165)
Issuance of common stock	12,072	63,083
Cash dividends paid	(32,222)	(30,084)
Tax benefits from share-based payment arrangements	1,183	1,013
Net cash (used in) provided by financing activities	(184,118)	149,269
Change in cash and cash equivalents	(54,353)	(37,125)
Cash and cash equivalents at beginning of period	228,558	324,878
Cash and cash equivalents at end of period	174,205	287,753
Supplemental disclosures of cash flow information:
Cash paid for interest	23,935	39,355
Cash paid for income taxes	19,328	16,217
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	11,279	10,682
Transfers from loans to other real estate	5,024	2,571
Acquisitions:
Fair value of assets acquired, excluding acquired cash and intangibles	0	165,885
Fair value of liabilities assumed	$ 0	$ 798,031