CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating activities:
Net income	$ 18,826	$ 16,160
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	2,809	2,739
Amortization of intangible assets	1,086	901
Net accretion of premiums & discounts on securities, loans and borrowings	(998)	(314)
Stock-based compensation	1,223	1,262
Provision for loan losses	1,644	1,050
Amortization of mortgage servicing rights	188	224
Income on bank-owned life insurance policies	(271)	(113)
Net gain on sale of loans and other assets	(171)	(388)
Net change in loans held for sale	562	3,976
Change in other assets and liabilities	3,997	(2,416)
Net cash provided by operating activities	28,895	23,081
Investing activities:
Proceeds from maturities of held-to-maturity investment securities	4,555	11,703
Proceeds from maturities of available-for-sale investment securities	36,742	36,760
Purchases of held-to-maturity investment securities	(103,633)	(2,299)
Purchases of available-for-sale investment securities	(549,254)	(86,795)
Net change other securities	(8,190)	7
Net decrease in loans	8,238	24,506
Cash paid for acquisition	0	(270)
Purchases of premises and equipment	(560)	(2,137)
Net cash used in investing activities	(612,102)	(18,525)
Financing activities:
Net increase in deposits	156,762	86,986
Net change in borrowings	182,146	(75)
Issuance of common stock	60,425	1,324
Cash dividends paid	(9,609)	(7,976)
Tax benefits from share-based payment arrangements	660	286
Net cash provided by financing activities	390,384	80,545
Change in cash and cash equivalents	(192,823)	85,101
Cash and cash equivalents at beginning of period	324,878	211,837
Cash and cash equivalents at end of period	132,055	296,938
Supplemental disclosures of cash flow information:
Cash paid for interest	13,824	14,882
Cash paid for income taxes	3,091	124
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	10,216	8,022
Transfers from loans to other real estate	$ 739	$ 912