Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating activities:
Net income	$ 43,646	$ 28,069
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for probable loan losses	2,078	7,419
Specific reserve, other real estate owned	138	(70)
Depreciation of bank premises and equipment	6,092	6,625
Gain on sale of bank premises and equipment	(2,956)	(21)
Gain on sale of other real estate owned	(233)	(39)
Accretion of investment securities discounts	(1,274)	(894)
Amortization of investment securities premiums	6,765	11,204
Investment securities transactions, net	(8,108)	(9,601)
Impairment charges on available-for-sale investment securities	90	310
Amortization of identified intangible assets	981	1,137
Stock based compensation expense	161	114
Earnings from affiliates and other investments	(3,109)	(4,702)
Deferred tax benefit	(1,666)	(2,098)
Decrease in accrued interest receivable	2,345	2,650
Net (increase) decrease in other assets	(365)	8,926
Net increase in other liabilities	16,630	4,404
Net cash provided by operating activities	61,215	53,433
Investing activities:
Proceeds from sales and calls of available for sale securities	258,277	178,124
Purchases of available for sale securities	(310,921)	(217,214)
Principal collected on mortgage-backed securities	171,405	396,105
Net increase in loans	(88,610)	(59,937)
Purchases of other investments	(681)	(512)
Distributions from other investments	10,281	9,878
Purchases of bank premises and equipment	(14,436)	(6,166)
Proceeds from sales of other real estate owned	5,559	4,410
Proceeds from sale of bank premises and equipment	3,298	21
Net cash provided by investing activities	34,172	304,709
Financing activities:
Net increase in non-interest bearing demand deposits	163,485	146,577
Net increase in savings and interest bearing demand deposits	40,450	1,413
Net decrease in time deposits	(11,117)	(118,660)
Net decrease in securities sold under repurchase agreements	(120,211)	(74,092)
Net decrease in other borrowed funds	(75,547)	(361,534)
Redemption of long-term debt	(10,310)
Purchases of treasury stock	(5,755)
Proceeds from stock transactions	120	13
Net cash used in financing activities	(18,885)	(406,283)
Increase (decrease) in cash and cash equivalents	76,502	(48,141)
Cash and cash equivalents at beginning of period	274,785	283,100
Cash and cash equivalents at end of period	351,287	234,959
Supplemental cash flow information:
Interest paid	12,594	15,590
Income taxes paid	5,652	5,000
Non-cash investing and financing activities:
Dividends declared, not yet paid	16,741	13,439
Net transfer from loans to other real estate owned	486	5,788
Purchases of available-for-sale securities not yet settled	$ 3,079	$ 37,545