CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities:
Net income	$ 41,363	$ 39,897
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	5,947	5,551
Amortization of intangible assets	2,319	2,131
Net accretion of premiums and discounts on securities, loans and borrowings	(2,359)	(2,584)
Stock-based compensation	2,107	2,036
Provision for loan losses	2,714	3,799
Amortization of mortgage servicing rights	276	365
Income from bank-owned life insurance policies	(523)	(536)
Gain on sales of investment securities	(63,799)	0
Loss on debt extinguishments	63,500	0
Net loss/(gain) from sale of loans and other assets	187	(82)
Net change in loans held for sale	(1,136)	576
Change in other assets and liabilities	5,134	789
Net cash provided by operating activities	55,730	51,942
Investing activities:
Proceeds from sales of available-for-sale investment securities	672,750	0
Proceeds from maturities of available-for-sale investment securities	113,335	103,709
Proceeds from maturities of held-to-maturity investment securities	24,015	12,602
Proceeds from sale of other investment securities	18,240	1
Purchases of available-for-sale investment securities	(439,448)	(724,530)
Purchases of held-to-maturity investment securities	(4,153)	(106,226)
Purchases of other securities	(2)	(19,123)
Net increase in loans	(72,551)	(94,829)
Purchases of premises and equipment	(7,355)	(4,132)
Net cash provided by (used in) investing activities	304,831	(832,528)
Financing activities:
Net increase in deposits	42,091	115,107
Net change in borrowings, net of payments of $565,142 and $110	(469,242)	429,591
Issuance of common stock	7,366	61,017
Cash dividends paid	(21,427)	(19,825)
Tax benefits from share-based payment arrangements	666	720
Net cash (used in) provided by financing activities	(440,546)	586,610
Change in cash and cash equivalents	(79,985)	(193,976)
Cash and cash equivalents at beginning of period	228,558	324,878
Cash and cash equivalents at end of period	148,573	130,902
Supplemental disclosures of cash flow information:
Cash paid for interest	18,358	26,775
Cash paid for income taxes	11,768	9,655
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	10,805	10,260
Transfers from loans to other real estate	$ 3,439	$ 1,977