Business Segments (Details 2) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Interest Income	$ 218,455	$ 214,314	$ 204,363	$ 432,769	$ 292,723
Interest expense	(15,903)	(15,239)	(11,830)	(31,142)	(14,175)
Net interest income	202,552	199,075	192,533	401,627	278,548
Provision for credit losses	(6,529)	(16,434)	(5,030)	(22,963)	(4,386)
(Loss) gain on securities	(186)	3,275	89	3,089	4,841
FDIC loss sharing expense, net	(5,107)	(4,399)	(8,525)	(9,506)	(19,955)
Total noninterest income	19,623	20,871	8,479	40,494	13,170
Foreclosed assets (expense) income, net	(2,340)	336	497	(2,004)	(1,364)
Intangible asset amortization	1,502	1,501	1,677	3,003	3,041
Acquisition, integration and reorganization costs	900	2,000	86,242	2,900	88,442
Total noninterest expense	85,276	84,360	169,200	169,636	219,364
Income Tax Expense (Benefit)	(45,287)	(46,073)	(15,552)	(91,360)	(30,833)
Net earnings from continuing operations	85,083	73,079	11,230	158,162	37,135
Loss from discontinued operations before taxes	0	0	(1,151)	0	(2,564)
Income tax benefit	0	0	476	0	1,064
Net loss from discontinued operations	0	0	(675)	0	(1,500)
Net earnings	(85,083)	(73,079)	(10,555)	(158,162)	(35,635)
Consolidated Entities [Member]
Segment Reporting Information [Line Items]
Interest Income	218,455	214,314	204,363	432,769	292,723
Interest expense	(15,903)	(15,239)	(11,830)	(31,142)	(14,175)
Intersegment interest income (expense), net	0	0	0	0	0
Net interest income	202,552	199,075	192,533	401,627	278,548
Provision for credit losses	(6,529)	(16,434)	5,030	(22,963)	4,386
(Loss) gain on securities	(186)	3,275	89	3,089	4,841
FDIC loss sharing expense, net	(5,107)	(4,399)	(8,525)	(9,506)	(19,955)
Other noninterest income	24,916	21,995	16,915	46,911	28,284
Total noninterest income	19,623	20,871	8,479	40,494	13,170
Foreclosed assets (expense) income, net	2,340	(336)	497	2,004	(1,364)
Intangible asset amortization	(1,502)	(1,501)	1,677	(3,003)	3,041
Acquisition, integration and reorganization costs	(900)	(2,000)	86,242	(2,900)	88,442
Other noninterest expense	(85,214)	(80,523)	80,784	(165,737)	129,245
Total noninterest expense	(85,276)	(84,360)	169,200	(169,636)	219,364
Intersegment noninterest income, net	0	0	0	0	0
Total noninterest expense, adjusted for intersegment noninterest net income	(85,276)	(84,360)	169,200	(169,636)	219,364
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	130,370	119,152	(26,782)	249,522	(67,968)
Income Tax Expense (Benefit)	45,287	46,073	(15,552)	91,360	(30,833)
Net earnings from continuing operations			11,230		37,135
Loss from discontinued operations before taxes			(1,151)		(2,564)
Income tax benefit			476		1,064
Net loss from discontinued operations			(675)		(1,500)
Net earnings	(85,083)		(10,555)	(158,162)	(35,635)
Operating Segments [Member] | Community Banking Segment [Member]
Segment Reporting Information [Line Items]
Interest Income	63,392	62,956	69,977	126,348	147,572
Interest expense	(11,273)	(10,661)	(7,450)	(21,934)	(8,677)
Intersegment interest income (expense), net	7,140	6,721	4,071	13,861	4,293
Net interest income	59,259	59,016	66,598	118,275	143,188
Provision for credit losses	734	8,064	(4,418)	8,798	(5,244)
(Loss) gain on securities	(186)	3,275	89	3,089	4,841
FDIC loss sharing expense, net	(5,107)	(4,399)	(8,525)	(9,506)	(19,955)
Other noninterest income	4,235	9,575	3,681	13,810	10,578
Total noninterest income	(1,058)	8,451	(4,755)	7,393	(4,536)
Foreclosed assets (expense) income, net	(351)	(44)	633	(395)	(1,228)
Intangible asset amortization	(1,390)	(1,389)	1,530	(2,779)	2,721
Acquisition, integration and reorganization costs	(806)	(1,890)	77,713	(2,696)	79,913
Other noninterest expense	(58,304)	(55,205)	50,801	(113,509)	91,086
Total noninterest expense	(60,851)	(58,528)	130,677	(119,379)	172,492
Intersegment noninterest income, net	28,857	26,563	(23,533)	55,420	(23,533)
Total noninterest expense, adjusted for intersegment noninterest net income	(31,994)	(31,965)	107,144	(63,959)	148,959
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	26,941	43,566	40,883	70,507	5,063
Income Tax Expense (Benefit)	10,484	16,873	11,375	27,357	(1,664)
Net earnings from continuing operations			(29,508)		(6,727)
Loss from discontinued operations before taxes			(1,151)		(2,564)
Income tax benefit			476		1,064
Net loss from discontinued operations			(675)		(1,500)
Net earnings	(16,457)	(26,693)	30,183	(43,150)	8,227
Operating Segments [Member] | National Lending Segment [Member]
Segment Reporting Information [Line Items]
Interest Income	154,816	151,219	132,742	306,035	143,507
Interest expense	(48)	(53)	(62)	(101)	(139)
Intersegment interest income (expense), net	(7,140)	(6,721)	(4,071)	(13,861)	(4,293)
Net interest income	147,628	144,445	128,609	292,073	139,075
Provision for credit losses	(7,263)	(24,406)	9,448	(31,669)	9,630
(Loss) gain on securities	0	0	0	0	0
FDIC loss sharing expense, net	0	0	0	0	0
Other noninterest income	14,465	5,142	12,487	19,607	16,932
Total noninterest income	14,465	5,142	12,487	19,607	16,932
Foreclosed assets (expense) income, net	(22)	(61)	(38)	(83)	(38)
Intangible asset amortization	(112)	(112)	147	(224)	320
Acquisition, integration and reorganization costs	0	0	7,474	0	7,474
Other noninterest expense	(24,164)	(22,837)	24,484	(47,001)	31,057
Total noninterest expense	(24,298)	(23,010)	32,067	(47,308)	38,813
Intersegment noninterest income, net	(28,857)	(26,563)	23,533	(55,420)	23,533
Total noninterest expense, adjusted for intersegment noninterest net income	(53,155)	(49,573)	55,600	(102,728)	62,346
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	101,675	75,608	(76,048)	177,283	(84,031)
Income Tax Expense (Benefit)	39,566	29,282	(30,259)	68,848	(33,590)
Net earnings from continuing operations			45,789		50,441
Loss from discontinued operations before taxes			0		0
Income tax benefit			0		0
Net loss from discontinued operations			0		0
Net earnings	(62,109)	(46,326)	(45,789)	(108,435)	(50,441)
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Interest Income	247	139	1,644	386	1,644
Interest expense	(4,582)	(4,525)	(4,318)	(9,107)	(5,359)
Intersegment interest income (expense), net	0	0	0	0	0
Net interest income	(4,335)	(4,386)	(2,674)	(8,721)	(3,715)
Provision for credit losses	0	(92)	0	(92)	0
(Loss) gain on securities	0	0	0	0	0
FDIC loss sharing expense, net	0	0	0	0	0
Other noninterest income	6,216	7,278	747	13,494	774
Total noninterest income	6,216	7,278	747	13,494	774
Foreclosed assets (expense) income, net	2,713	(231)	(98)	2,482	(98)
Intangible asset amortization	0	0	0	0	0
Acquisition, integration and reorganization costs	(94)	(110)	1,055	(204)	1,055
Other noninterest expense	(2,746)	(2,481)	5,499	(5,227)	7,102
Total noninterest expense	(127)	(2,822)	6,456	(2,949)	8,059
Intersegment noninterest income, net	0	0	0	0	0
Total noninterest expense, adjusted for intersegment noninterest net income	(127)	(2,822)	6,456	(2,949)	8,059
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	1,754	(22)	8,383	1,732	11,000
Income Tax Expense (Benefit)	(4,763)	(82)	3,332	(4,845)	4,421
Net earnings from continuing operations			(5,051)		(6,579)
Loss from discontinued operations before taxes			0		0
Income tax benefit			0		0
Net loss from discontinued operations			0		0
Net earnings	$ (6,517)	$ (60)	$ 5,051	$ (6,577)	$ 6,579