Business Segments (Details 2) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Interest Income	$ 207,672	$ 218,455	$ 202,356	$ 640,441	$ 495,079
Interest expense	(15,152)	(15,903)	(13,510)	(46,294)	(27,685)
Net interest income	192,520	202,552	188,846	594,147	467,394
Provision for credit losses	(8,746)	(6,529)	(5,050)	(31,709)	(9,436)
(Loss) gain on securities	655	(186)	0	3,744	4,841
FDIC loss sharing expense, net	(4,449)	(5,107)	(7,415)	(13,955)	(27,370)
Total noninterest income	15,758	19,623	16,314	56,252	29,484
Foreclosed assets (expense) income, net	(4,521)	2,340	(4,827)	(2,517)	(3,463)
Intangible asset amortization	(1,497)	(1,502)	(1,608)	(4,500)	(4,649)
Acquisition, integration and reorganization costs	(747)	(900)	(5,193)	(3,647)	(93,635)
Total noninterest expense	(90,139)	(85,276)	(94,923)	(259,775)	(314,287)
Income tax (expense) benefit	(39,777)	(45,287)	(42,911)	(131,137)	(73,744)
Net earnings from continuing operations	69,616	85,083	62,276	227,778	99,411
Loss from discontinued operations before taxes	0	0	(8)	0	(2,572)
Income tax benefit	0	0	3	0	1,067
Net loss from discontinued operations	0	0	(5)	0	(1,505)
Net earnings	(69,616)	(85,083)	(62,271)	(227,778)	(97,906)
Consolidated Entities [Member]
Segment Reporting Information [Line Items]
Interest Income	207,672	218,455	202,356	640,441	495,079
Interest expense	(15,152)	(15,903)	(13,510)	(46,294)	(27,685)
Intersegment interest income (expense), net	0	0	0	0	0
Net interest income	192,520	202,552	188,846	594,147	467,394
Provision for credit losses	(8,746)	(6,529)	(5,050)	(31,709)	(9,436)
(Loss) gain on securities	655	(186)		3,744	4,841
FDIC loss sharing expense, net	(4,449)	(5,107)	(7,415)	(13,955)	(27,370)
Other noninterest income	19,552	24,916	23,729	66,463	52,013
Total noninterest income	15,758	19,623	16,314	56,252	29,484
Foreclosed assets (expense) income, net	(4,521)	2,340	(4,827)	(2,517)	(3,463)
Intangible asset amortization	(1,497)	(1,502)	(1,608)	(4,500)	(4,649)
Acquisition, integration and reorganization costs	(747)	(900)	(5,193)	(3,647)	(93,635)
Other noninterest expense	(83,374)	(85,214)	(83,295)	(249,111)	(212,540)
Total noninterest expense	(90,139)	(85,276)	(94,923)	(259,775)	(314,287)
Intersegment noninterest income, net	0	0	0	0	0
Total noninterest expense - adjusted	(90,139)	(85,276)	(94,923)	(259,775)	(314,287)
Earnings (loss) before taxes	109,393	130,370	105,187	358,915	173,155
Income tax (expense) benefit	(39,777)	(45,287)	(42,911)	(131,137)	(73,744)
Net earnings from continuing operations			62,276		99,411
Loss from discontinued operations before taxes			(8)		(2,572)
Income tax benefit			3		1,067
Net loss from discontinued operations			(5)		(1,505)
Net earnings	(69,616)	(85,083)	(62,271)	(227,778)	(97,906)
Operating Segments [Member] | Community Banking Segment [Member]
Segment Reporting Information [Line Items]
Interest Income	58,368	63,392	67,132	184,716	214,704
Interest expense	(10,430)	(11,273)	(8,851)	(32,364)	(17,528)
Intersegment interest income (expense), net	6,629	7,140	5,250	20,490	9,543
Net interest income	54,567	59,259	63,531	172,842	206,719
Provision for credit losses	1,309	734	6,314	10,107	11,558
(Loss) gain on securities	655	(186)		3,744	4,841
FDIC loss sharing expense, net	(4,449)	(5,107)	(7,415)	(13,955)	(27,370)
Other noninterest income	7,956	4,235	7,566	21,766	18,144
Total noninterest income	4,162	(1,058)	151	11,555	(4,385)
Foreclosed assets (expense) income, net	(4,787)	(351)	(4,627)	(5,182)	(3,399)
Intangible asset amortization	(1,385)	(1,390)	(1,517)	(4,164)	(4,238)
Acquisition, integration and reorganization costs	(747)	(806)	(3,953)	(3,443)	(83,866)
Other noninterest expense	(56,318)	(58,304)	(53,078)	(169,827)	(144,164)
Total noninterest expense	(63,237)	(60,851)	(63,175)	(182,616)	(235,667)
Intersegment noninterest income, net	28,280	28,857	26,411	83,700	49,944
Total noninterest expense - adjusted	(34,957)	(31,994)	(36,764)	(98,916)	(185,723)
Earnings (loss) before taxes	25,081	26,941	33,232	95,588	28,169
Income tax (expense) benefit	(9,584)	(10,484)	(14,576)	(36,941)	(16,240)
Net earnings from continuing operations			18,656		11,929
Loss from discontinued operations before taxes			(8)		(2,572)
Income tax benefit			3		1,067
Net loss from discontinued operations			(5)		(1,505)
Net earnings	(15,497)	(16,457)	(18,651)	(58,647)	(10,424)
Operating Segments [Member] | National Lending Segment [Member]
Segment Reporting Information [Line Items]
Interest Income	148,264	154,816	134,624	454,299	278,131
Interest expense	(42)	(48)	(45)	(143)	(184)
Intersegment interest income (expense), net	(6,629)	(7,140)	(5,250)	(20,490)	(9,543)
Net interest income	141,593	147,628	129,329	433,666	268,404
Provision for credit losses	(10,145)	(7,263)	(11,364)	(41,814)	(20,994)
(Loss) gain on securities	0	0		0	0
FDIC loss sharing expense, net	0	0	0	0	0
Other noninterest income	7,478	14,465	9,953	27,085	26,885
Total noninterest income	7,478	14,465	9,953	27,085	26,885
Foreclosed assets (expense) income, net	39	(22)	(322)	(44)	(284)
Intangible asset amortization	(112)	(112)	(91)	(336)	(411)
Acquisition, integration and reorganization costs	0	0	(1,240)	0	(8,714)
Other noninterest expense	(23,763)	(24,164)	(24,835)	(70,764)	(55,892)
Total noninterest expense	(23,836)	(24,298)	(26,488)	(71,144)	(65,301)
Intersegment noninterest income, net	(28,280)	(28,857)	(26,411)	(83,700)	(49,944)
Total noninterest expense - adjusted	(52,116)	(53,155)	(52,899)	(154,844)	(115,245)
Earnings (loss) before taxes	86,810	101,675	75,019	264,093	159,050
Income tax (expense) benefit	(33,172)	(39,566)	(30,113)	(102,020)	(63,703)
Net earnings from continuing operations			44,906		95,347
Loss from discontinued operations before taxes			0		0
Income tax benefit			0		0
Net loss from discontinued operations			0		0
Net earnings	(53,638)	(62,109)	(44,906)	(162,073)	(95,347)
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Interest Income	1,040	247	600	1,426	2,244
Interest expense	(4,680)	(4,582)	(4,614)	(13,787)	(9,973)
Intersegment interest income (expense), net	0	0	0	0	0
Net interest income	(3,640)	(4,335)	(4,014)	(12,361)	(7,729)
Provision for credit losses	90	0	0	(2)	0
(Loss) gain on securities	0	0		0	0
FDIC loss sharing expense, net	0	0	0	0	0
Other noninterest income	4,118	6,216	6,210	17,612	6,984
Total noninterest income	4,118	6,216	6,210	17,612	6,984
Foreclosed assets (expense) income, net	227	2,713	122	2,709	220
Intangible asset amortization	0	0	0	0	0
Acquisition, integration and reorganization costs	0	(94)	0	(204)	(1,055)
Other noninterest expense	(3,293)	(2,746)	(5,382)	(8,520)	(12,484)
Total noninterest expense	(3,066)	(127)	(5,260)	(6,015)	(13,319)
Intersegment noninterest income, net	0	0	0	0	0
Total noninterest expense - adjusted	(3,066)	(127)	(5,260)	(6,015)	(13,319)
Earnings (loss) before taxes	(2,498)	1,754	(3,064)	(766)	(14,064)
Income tax (expense) benefit	2,979	4,763	1,778	7,824	6,199
Net earnings from continuing operations			(1,286)		(7,865)
Loss from discontinued operations before taxes			0		0
Income tax benefit			0		0
Net loss from discontinued operations			0		0
Net earnings	$ (481)	$ (6,517)	$ 1,286	$ (7,058)	$ 7,865