Consolidated Statements of Cash Flows (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash Flows from Operating Activities:
Net income	$ 80,656,000	$ 88,047,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, and accretion	31,184,000	30,051,000
Provision for loan and lease losses	9,000,000	24,000,000
Stock compensation expense	2,821,000	1,473,000
Realized loss on available-for-sale securities, net	(3,285,000)	53,000
Deferred income tax (benefit) expense	30,315,000	30,552,000
Gain on sale of loans and leases	(4,728,000)	(9,256,000)
Gain on sale of foreclosed assets	(95,000)	(470,000)
(Gain) loss on sale of fixed assets	(69,000)	285,000
Mortgage loans originated for sale	(215,753,000)	(272,513,000)
Proceeds from sale of mortgage loans originated for sale	196,500,000	287,009,000
Increase in cash surrender value of bank-owned life insurance	(3,690,000)	(2,843,000)
Decrease (increase) in accrued interest receivable	2,812,000	(2,361,000)
(Decrease) increase in accrued interest payable	1,549,000	1,627,000
Decrease in accrued expenses and taxes payable	(11,035,000)	(5,224,000)
Other, net	(1,659,000)	8,301,000
Net cash provided by operating activities	114,523,000	178,731,000
Cash Flows from Investing Activities:
Net decrease in restricted short-term investments	(220,000)	28,929,000
Activity in available-for-sale securities:
Sales	42,000	33,763,000
Maturities, repayments, and calls	216,865,000	354,445,000
Purchases	0	(224,074,000)
Net decrease in restricted investment in bank stock	16,543,000	1,685,000
Net increase in loans and leases	(108,859,000)	(301,026,000)
Purchase of bank-owned life insurance	0	(4,843,000)
Proceeds from bank-owned life insurance	2,692,000	6,678,000
Proceeds from sale of foreclosed assets	10,724,000	12,661,000
Additions to premises and equipment, net	(4,919,000)	(6,761,000)
Net cash provided by (used in) investing activities	132,868,000	(98,543,000)
Cash Flows from Financing Activities:
Net increase in deposits	447,842,000	184,186,000
Net increase (decrease) in other short-term borrowings	(28,661,000)	(111,512,000)
Net decrease in short-term FHLB borrowings	(400,000,000)	(28,000,000)
Repayment of long-term FHLB borrowings	(3,057,000)	(8,005,000)
Repayment of long-term debt	(89,557,000)	(24,436,000)
Proceeds from issuance of common stock	3,555,000	4,621,000
Purchase of treasury stock	(544,000)	(25,000)
Cash dividends paid	(30,007,000)	(14,948,000)
Net cash (used in) provided by financing activities	(100,429,000)	1,881,000
Net change in cash and cash equivalents	146,962,000	82,069,000
Cash and cash equivalents at January 1	343,324,000	316,592,000
Cash and cash equivalents at June 30	490,286,000	398,661,000
Supplemental Disclosure of Cash Flow Information
Cash paid for interest on deposits and borrowings	43,866,000	50,880,000
Income tax payments (refunds)	(1,958,000)	(21,006,000)
Supplemental Schedule of Noncash Activities
Real estate acquired in settlement of loans	6,687,000	6,987,000
Securities Sold Not Settled	$ 2,729	$ 0