Segment Data (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Continuing operations of operating segments
Total interest income	$ 127,425	$ 164,720	$ 269,577	$ 336,134
Interest expense	45,807	60,757	92,559	125,758
Provision for loan losses	1,523	25,262	46,332	244,202
Operating expenses	55,322	53,591	109,583	116,796
Total other (expense) income	9,070	(34,806)	27,061	(57,081)
Net income (loss) from continuing operations before income taxes	33,843	(9,696)	48,164	(207,703)
Income tax expense (benefit)	17,249	(4,174)	28,411	16,832
Net income (loss) from continuing operations	16,594	(5,522)	19,753	(224,535)
Total assets	9,314,944		9,314,944		9,445,407
CapitalSource Bank [Member]
Continuing operations of operating segments
Total interest income	90,490	78,926	182,294	160,380
Interest expense	15,612	16,431	30,822	33,732
Provision for loan losses	(1,331)	5,094	9,911	92,798
Operating expenses	32,594	29,248	65,535	53,583
Total other (expense) income	3,000	7,067	5,965	15,226
Net income (loss) from continuing operations before income taxes	46,615	35,220	81,991	(4,507)
Income tax expense (benefit)	18,840	(2,463)	21,935	(2,519)
Net income (loss) from continuing operations	27,775	37,683	60,056	(1,988)
Total assets	6,371,806		6,371,806		6,117,368
Other Commercial Finance [Member]
Continuing operations of operating segments
Total interest income	40,701	87,333	88,315	179,666
Interest expense	30,195	44,326	61,737	92,026
Provision for loan losses	2,854	20,168	36,421	151,404
Operating expenses	41,676	40,392	83,002	90,899
Total other (expense) income	24,751	(25,690)	57,105	(44,668)
Net income (loss) from continuing operations before income taxes	(9,273)	(43,243)	(35,740)	(199,331)
Income tax expense (benefit)	(1,591)	(1,711)	6,476	19,351
Net income (loss) from continuing operations	(7,682)	(41,532)	(42,216)	(218,682)
Total assets	3,024,484		3,024,484		3,418,897
Intercompany Eliminations [Member]
Continuing operations of operating segments
Total interest income	(3,766)	(1,539)	(1,032)	(3,912)
Operating expenses	(18,948)	(16,049)	(38,954)	(27,686)
Total other (expense) income	(18,681)	(16,183)	(36,009)	(27,639)
Net income (loss) from continuing operations before income taxes	(3,499)	(1,673)	1,913	(3,865)
Net income (loss) from continuing operations	(3,499)	(1,673)	1,913	(3,865)
Total assets	$ (81,346)		$ (81,346)		$ (90,858)