CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities:
Net income	$ 45,850	$ 41,363
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	6,526	5,947
Amortization of intangible assets	2,242	2,319
Net accretion of premiums and discounts on securities and borrowings	(3,708)	(2,359)
Stock-based compensation	2,088	2,107
Provision for loan losses	2,900	2,714
Amortization of mortgage servicing rights	228	276
Income from bank-owned life insurance policies	(511)	(523)
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	(202)	187
Net change in loans held for sale	148	(1,136)
Change in other assets and liabilities	560	5,134
Net cash provided by operating activities	56,121	55,730
Investing activities:
Proceeds from sales of available-for-sale investment securities	0	672,750
Proceeds from maturities of available-for-sale investment securities	67,557	113,335
Proceeds from maturities of held-to-maturity investment securities	0	24,015
Proceeds from maturities of other investment securities	14	0
Proceeds from sale of other investment securities	0	18,240
Purchases of available-for-sale investment securities	(294,417)	(439,448)
Purchases of held-to-maturity investment securities	0	(4,153)
Purchases of other securities	(8,105)	(2)
Net increase in loans	(41,324)	(72,551)
Cash paid for acquisition, net of cash acquired of $0 and $0, respectively	(924)	0
Purchases of premises and equipment, net	(3,827)	(7,355)
Net cash (used in)/provided by investing activities	(281,026)	304,831
Financing activities:
Net increase in deposits	75,251	42,091
Net change in borrowings, net of payments of $5 and $565,142	177,495	(469,242)
Issuance of common stock	5,599	7,366
Cash dividends paid	(22,619)	(21,427)
Tax benefits from share-based payment arrangements	1,435	666
Net cash provided by/(used in) financing activities	237,161	(440,546)
Change in cash and cash equivalents	12,256	(79,985)
Cash and cash equivalents at beginning of period	149,647	228,558
Cash and cash equivalents at end of period	161,903	148,573
Supplemental disclosures of cash flow information:
Cash paid for interest	6,178	18,358
Cash paid for income taxes	11,464	11,768
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	11,434	10,805
Transfers from loans to other real estate	$ 1,550	$ 3,439