CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:
Net income	$ 78,829	$ 77,068	$ 73,142
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	12,236	11,482	11,374
Amortization of intangible assets	4,469	4,607	4,381
Net accretion of premiums & discounts on securities, loans and borrowings	(5,959)	(9,379)	(5,373)
Stock-based compensation	3,961	3,668	3,784
Provision for loan losses	7,992	9,108	4,736
Provision for deferred income taxes	7,130	12,032	12,942
Amortization of mortgage servicing rights	529	687	868
Income from bank-owned life insurance policies	(1,066)	(1,121)	(894)
Gain on sales of investment securities, net	(80,768)	(291)	(30)
Loss on debt extinguishments	87,336	0	91
Net loss (gain) on sale of loans and other assets	257	247	(422)
Net change in loans originated for sale	(515)	608	4,047
Change in other assets and liabilities	(11,247)	(292)	(14,268)
Net cash provided by (used in) operating activities	103,184	108,424	94,378
Investing activities:
Proceeds from sales of available-for-sale investment securities	713,694	5,378	15,330
Proceeds from sales of held-to-maturity investment securities	450,032	0	0
Proceeds from sales of other securities	26,649	278	1,032
Proceeds from maturities of held-to-maturity investment securities	31,595	28,340	65,062
Proceeds from maturities of available-for-sale investment securities	234,021	215,223	254,368
Purchases of held-to-maturity investment securities	(8,308)	(110,925)	(13,292)
Purchases of available-for-sale investment securities	(923,588)	(752,891)	(353,498)
Purchases of other securities	0	(615)	(2,908)
Net change in loans	(248,962)	(239,174)	16,078
Cash received for acquisitions, net of cash acquired of $291,990, $5,510, and $26,901, respectively	291,980	600,972	4,746
Purchases of premises and equipment	(13,855)	(10,846)	(9,613)
Net cash (used in) provided by investing activities	553,258	(264,260)	(22,695)
Financing activities:
Net change in deposits	(35,451)	34,832	89,646
Net change in borrowings, net of payments of $815,384, $220 and $25,938	(673,484)	(220)	(19,938)
Issuance of common stock	15,239	64,145	5,351
Cash dividends paid	(43,482)	(40,765)	(34,404)
Tax benefits from share-based payment arrangements	1,825	1,524	703
Net cash provided by (used in) financing activities	(735,353)	59,516	41,358
Change in cash and cash equivalents	(78,911)	(96,320)	113,041
Cash and cash equivalents at beginning of year	228,558	324,878	211,837
Cash and cash equivalents at end of year	149,647	228,558	324,878
Supplemental disclosures of cash flow information:
Cash paid for interest	30,141	51,541	61,564
Cash paid for income taxes	23,648	16,462	20,810
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	11,332	10,699	9,609
Transfers from loans to other real estate	8,325	5,059	5,186
Transfer of investment securities from held-to-maturity to available-for-sale	198,890	0	0
Acquisitions:
Fair value of assets acquired, excluding acquired cash and intangibles	3,678	165,885	815,824
Fair value of liabilities assumed	$ 303,494	$ 798,031	$ 791,222