Business Segments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Segment Reporting Information [Line Items]
Interest Income	$ 214,314	$ 209,696	$ 88,360
Interest expense	(15,239)	(14,713)	(2,345)
Intersegment interest income (expense), net	0	0	0
Net interest income	199,075	194,983	86,015
Provision for Loan, Lease, and Other Losses	(16,434)	(2,063)	644
Gain on securities	3,275	0	4,752
FDIC loss sharing expense, net	(4,399)	(4,360)	(11,430)
Other noninterest income	21,995	17,063	11,369
Total noninterest income	20,871	12,703	4,691
Foreclosed assets (expense) income, net	(336)	(1,938)	1,861
Intangible asset amortization	(1,501)	(1,619)	(1,364)
Acquisition, integration and reorganization costs	(2,000)	(7,381)	(2,200)
Other noninterest expense	(80,523)	(80,367)	(48,461)
Total noninterest expense	(84,360)	(91,305)	(50,164)
Intersegment noninterest income, net	0	0
Total noninterest expense, adjusted for intersegment noninterest net income	(84,360)	(91,305)
Earnings (loss) from continuing operations before taxes	119,152	114,318	41,186
Income Tax Expense (Benefit)	(46,073)	(43,261)	(15,281)
Net income before income taxes		71,057	25,905
Loss from discontinued operations before taxes	0	(105)	(1,413)
Income tax benefit	0	47	588
Net loss from discontinued operations	0	(58)	(825)
Net earnings	73,079	70,999	25,080
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net earnings			25,080
Operating Segments [Member] | National Lending Segment [Member]
Segment Reporting Information [Line Items]
Interest Income	151,219	144,546	10,765
Interest expense	(53)	(46)	(77)
Intersegment interest income (expense), net	(6,721)	(6,173)	(222)
Net interest income	144,445	138,327	10,466
Provision for Loan, Lease, and Other Losses	(24,406)	(11,816)	(182)
Gain on securities	0		0
FDIC loss sharing expense, net	0	0	0
Other noninterest income	5,142	7,330	4,445
Total noninterest income	5,142	7,330	4,445
Foreclosed assets (expense) income, net	(61)	(18)	0
Intangible asset amortization	(112)	(112)	(173)
Acquisition, integration and reorganization costs	0	0	0
Other noninterest expense	(22,837)	(24,526)	(6,573)
Total noninterest expense	(23,010)	(24,656)	(6,746)
Intersegment noninterest income, net	(26,563)	(21,953)
Total noninterest expense, adjusted for intersegment noninterest net income	(49,573)	(46,609)
Earnings (loss) from continuing operations before taxes	75,608	87,232	7,983
Income Tax Expense (Benefit)	(29,282)	(34,781)	(3,331)
Net income before income taxes		52,451	4,652
Loss from discontinued operations before taxes		0	0
Income tax benefit		0	0
Net loss from discontinued operations		0	0
Net earnings	46,326	52,451	4,652
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Interest Income	139	183	0
Interest expense	(4,525)	(4,598)	(1,041)
Intersegment interest income (expense), net	0	0	0
Net interest income	(4,386)	(4,415)	(1,041)
Provision for Loan, Lease, and Other Losses	(92)	0	0
Gain on securities	0		0
FDIC loss sharing expense, net	0	0	0
Other noninterest income	7,278	2,708	27
Total noninterest income	7,278	2,708	27
Foreclosed assets (expense) income, net	(231)	366	0
Intangible asset amortization	0	0	0
Acquisition, integration and reorganization costs	(110)	0	0
Other noninterest expense	(2,481)	(4,236)	(1,603)
Total noninterest expense	(2,822)	(3,870)	(1,603)
Intersegment noninterest income, net	0	0
Total noninterest expense, adjusted for intersegment noninterest net income	(2,822)	(3,870)
Earnings (loss) from continuing operations before taxes	(22)	(5,577)	(2,617)
Income Tax Expense (Benefit)	82	5,171	1,089
Net income before income taxes		(406)	(1,528)
Loss from discontinued operations before taxes		0	0
Income tax benefit		0	0
Net loss from discontinued operations		0	0
Net earnings	60	(406)	(1,528)
Operating Segments [Member] | Community Banking Segment [Member]
Segment Reporting Information [Line Items]
Interest Income	62,956	64,967	77,595
Interest expense	(10,661)	(10,069)	(1,227)
Intersegment interest income (expense), net	6,721	6,173	222
Net interest income	59,016	61,071	76,590
Provision for Loan, Lease, and Other Losses	8,064	9,753	826
Gain on securities	3,275		4,752
FDIC loss sharing expense, net	(4,399)	(4,360)	(11,430)
Other noninterest income	9,575	7,025	6,897
Total noninterest income	8,451	2,665	219
Foreclosed assets (expense) income, net	(44)	(2,286)	1,861
Intangible asset amortization	(1,389)	(1,507)	(1,191)
Acquisition, integration and reorganization costs	(1,890)	(7,381)	(2,200)
Other noninterest expense	(55,205)	(51,605)	(40,285)
Total noninterest expense	(58,528)	(62,779)	(41,815)
Intersegment noninterest income, net	26,563	21,953
Total noninterest expense, adjusted for intersegment noninterest net income	(31,965)	(40,826)
Earnings (loss) from continuing operations before taxes	43,566	32,663	35,820
Income Tax Expense (Benefit)	(16,873)	(13,651)	(13,039)
Net income before income taxes		19,012	22,781
Loss from discontinued operations before taxes		(105)	(1,413)
Income tax benefit		47	588
Net loss from discontinued operations		(58)	(825)
Net earnings	$ 26,693	$ 18,954	$ 21,956