Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Activities:
Net income	$ 76,759	$ 52,206	$ 74,775
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,605	13,526	15,549
Provision for loan losses	38,732	65,991	54,590
Losses (gains) on other real estate owned	4,922	(1,960)	768
Deferred tax expense (benefit)	26,577	(11,612)	(6,953)
Increase in cash surrender value of life insurance contracts	(12,169)	(8,022)	(6,396)
Gain on acquisition			(20,732)
Loss (gain) on sales/paydowns of securities available for sale, net	91		(69)
(Gain) on disposal of other assets	(424)	(316)	(1,478)
Net (increase) decrease in loans originated for sale	(1,560)	22,032	(13,822)
Net amortization of securities premium/discount	29,523	7,071	917
Amortization of intangible assets	16,551	2,728	1,417
Stock-based compensation expense	7,196	4,077	3,254
(Decrease) increase in interest payable and other liabilities	(99,986)	(12,405)	16,702
Decrease (increase) in FDIC indemnification asset	116,251	(3,530)
Decrease (increase) in other assets	46,082	65,963	(100,474)
Other, net	(104)	(951)	94
Net cash provided by operating activities	273,046	194,798	18,142
Investing Activities:
Net (increase) decrease in interest-bearing time deposits	(104,647)	218,015	(558,271)
Proceeds from sales of securities available for sale	342,864		10,202
Proceeds from maturities of securities available for sale	998,726	603,102	599,066
Purchases of securities available for sale	(1,732,757)	(489,835)	(509,304)
Net decrease (increase) in federal funds sold and short-term investments	281,639	(59,573)	317,319
Net decrease in loans	86,057	40,400	17,906
Purchases of property and equipment	(72,975)	(21,899)	(12,305)
Proceeds from sales of property and equipment	9,326	2,220	2,700
Proceeds from sales of other real estate	80,125	41,945	8,015
Cash paid for acquisition, net of cash received	(74,736)		378,367
Net cash paid for divestiture of branches	(114,645)
Net cash (used in) provided by investing activities	(301,023)	334,375	253,695
Financing Activities:
Net decrease in deposits	(65,298)	(420,093)	(298,062)
Increase (decrease) in other short-term borrowings	123,525	(120,031)	(21,225)
Proceeds from issuance of long-term debt	150,317
Repayments of long-term notes	(16,641)	(295)	(166)
Proceeds from issuance of short-term notes			1,609,399
Repayments of short-term notes	(10,172)	(20,000)	(1,694,898)
Dividends paid	(70,617)	(35,721)	(32,011)
Proceeds from exercise of stock options	1,025	1,618	2,213
Proceeds from stock offering	213,994		167,372
Excess tax benefit from stock option exercises	104	322	480
Net cash provided by (used in) financing activities	326,237	(594,200)	(266,898)
(Increase) decrease in cash and due from banks	298,260	(65,027)	4,939
Cash and due from banks at beginning of year	139,687	204,714	199,775
Cash and due from banks at end of year	437,947	139,687	204,714
Supplemental Information
Income taxes paid	24,529	22,878	5,810
Interest paid, including capitalized interest of $12, $70, and $20, respectively	66,695	83,161	96,797
Supplemental Information for Non-Cash Investing and Financing Activities
Assets acquired in settlement of loans	117,690	59,758	20,023
Acquisitions
Fair value of assets acquired	11,156,952		1,715,266
Fair value of liabilities assumed	(10,130,706)		(1,694,534)
Net identifiable assets acquired	1,026,246		20,732
Common stock issued in connection with acquisition	$ 1,308,044