Guarantor Information (Details 2) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Operating activities:
Net income (loss)	$ 16,594	$ 18,340	$ 19,753	$ (193,350)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Stock option expense			3,026	2,402
Restricted stock expense			3,511	6,141
Gain on extinguishment of debt				(1,096)
Amortization of deferred loan fees and discounts			(40,869)	(38,771)
Paid-in-kind interest on loans			29,804	6,143
Provision for loan losses	1,523	25,262	46,332	244,202
Provision for unfunded commitments				(510)
Amortization of deferred financing fees and discounts			15,956	30,925
Depreciation and amortization			74	523
Benefit for deferred income taxes			50,354	25,066
Non-cash (gain) loss on investments, net			(35,708)	478
Gain on assets acquired through business combination				(3,724)
Non-cash loss on foreclosed assets and other property and equipment disposals			17,765	57,302
Unrealized loss (gain) on derivatives and foreign currencies, net			2,130	(13,110)
Accretion of discount on commercial real estate "A" participation interest				(8,222)
Decrease in interest receivable			19,276	20,367
Decrease in loans held for sale, net			200,950	7,507
Decrease (increase) in other assets			72,029	(6,095)
Decrease in other liabilities			(76,566)	(35,537)
Cash provided by operating activities			327,817	100,641
Investing activities:
Decrease in restricted cash			27,330	26,125
Decrease in commercial real estate "A" participation interest, net				368,324
Decrease in loans, net			364,546	343,501
Assets acquired through business combination, net of cash acquired				(98,800)
Reduction (acquisition) of marketable securities, available for sale, net			94,790	(542,526)
Reduction of marketable securities, held to maturity, net			54,689	46,304
Reduction of other investments, net			23,683	20,352
Cash received for real estate				339,643
Acquisition of property and equipment, net			(7,094)	(757)
Cash provided by investing activities			557,944	502,166
Financing activities:
Payment of deferred financing fees				(4,430)
Deposits accepted, net of repayments			164,517	86,892
Repayments on credit facilities, net			(68,792)	(206,696)
Borrowings of term debt				14,784
Repayments of term debt			(282,985)	(710,160)
Borrowings under (repayments of) other borrowings			67,958	(233,154)
Proceeds from exercise of options			804	347
Payment of dividends			(6,447)	(6,485)
Cash used in financing activities			(124,945)	(1,058,902)
Increase (decrease) in cash and cash equivalents			760,816	(456,095)
Cash and cash equivalents as of beginning of period			820,450	1,177,020
Cash and cash equivalents as of end of period	1,581,266	720,925	1,581,266	720,925
CapitalSource Inc. [Member]
Operating activities:
Net income (loss)	16,594	18,340	19,753	(193,350)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Gain on extinguishment of debt				(1,096)
Amortization of deferred financing fees and discounts			14,150	15,186
Benefit for deferred income taxes			21,513	(869)
Decrease (increase) in other assets			(3,735)	1,458
Decrease in other liabilities			(1,571)	230
Net transfers with subsidiaries			(139,081)	362,424
Cash provided by operating activities			(88,971)	183,983
Financing activities:
Payment of deferred financing fees				(581)
Repayments on credit facilities, net				(100,054)
Borrowings under (repayments of) other borrowings				(34,144)
Proceeds from exercise of options			804	347
Payment of dividends			(6,447)	(6,485)
Cash used in financing activities			(5,643)	(140,917)
Increase (decrease) in cash and cash equivalents			(94,614)	43,066
Cash and cash equivalents as of beginning of period			94,614	99,103
Cash and cash equivalents as of end of period	0	142,169	0	142,169
Non-Guarantor Subsidiaries [Member]
Operating activities:
Net income (loss)	37,157	71,105	110,200	69,515
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Stock option expense			964	876
Restricted stock expense			1,584	1,057
Amortization of deferred loan fees and discounts			(29,609)	(18,649)
Paid-in-kind interest on loans			29,827	2,292
Provision for loan losses	6,340	12,310	5,543	97,858
Provision for unfunded commitments				(510)
Amortization of deferred financing fees and discounts			2,783	11,432
Depreciation and amortization			(1,323)	(2,692)
Benefit for deferred income taxes			1,488	4,463
Non-cash (gain) loss on investments, net			(30,178)	1,660
Gain on assets acquired through business combination				(3,724)
Non-cash loss on foreclosed assets and other property and equipment disposals			11,638	7,189
Unrealized loss (gain) on derivatives and foreign currencies, net			1,650	(9,820)
Accretion of discount on commercial real estate "A" participation interest				(8,222)
Decrease in interest receivable			(3,255)	(6,256)
Decrease in loans held for sale, net			173,160	335
Decrease (increase) in intercompany receivable			9
Decrease (increase) in other assets			32,909	(5,063)
Decrease in other liabilities			(54,357)	(59,362)
Net transfers with subsidiaries			(241,270)	(50,503)
Cash provided by operating activities			11,763	31,876
Investing activities:
Decrease in restricted cash			2,907	53,056
Decrease in commercial real estate "A" participation interest, net				368,324
Decrease in loans, net			25,878	136,280
Assets acquired through business combination, net of cash acquired				(98,800)
Reduction (acquisition) of marketable securities, available for sale, net			75,790	(542,526)
Reduction of marketable securities, held to maturity, net			54,689	46,304
Reduction of other investments, net			26,269	(8,643)
Acquisition of property and equipment, net			(6,476)	(683)
Cash provided by investing activities			179,057	(46,688)
Financing activities:
Payment of deferred financing fees				(8,021)
Deposits accepted, net of repayments			164,517	86,892
(Decrease) increase in intercompany payable			(46,850)
Repayments on credit facilities, net			(66,890)	(65,703)
Repayments of term debt			(282,985)	(472,646)
Borrowings under (repayments of) other borrowings			68,000	65,000
Cash used in financing activities			(164,208)	(394,478)
Increase (decrease) in cash and cash equivalents			26,612	(409,290)
Cash and cash equivalents as of beginning of period			353,666	760,343
Cash and cash equivalents as of end of period	380,278	351,053	380,278	351,053
Guarantor Subsidiaries [Member]
Operating activities:
Net income (loss)	46,065	72,375	54,028	52,814
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Stock option expense			2,062	1,526
Restricted stock expense			1,927	5,084
Amortization of deferred loan fees and discounts			(5,324)	(13,497)
Paid-in-kind interest on loans			372	3,005
Provision for loan losses	(3,258)	(24,316)	36,945	(23,524)
Amortization of deferred financing fees and discounts			179	209
Depreciation and amortization			1,397	1,774
Benefit for deferred income taxes				(195)
Non-cash (gain) loss on investments, net			112	119
Non-cash loss on foreclosed assets and other property and equipment disposals			(344)	3,626
Unrealized loss (gain) on derivatives and foreign currencies, net			(4,946)	(26,256)
Decrease in interest receivable			(5,688)	25,088
Decrease in loans held for sale, net			11,353	(296)
Decrease (increase) in intercompany receivable			67,976	(12,663)
Decrease (increase) in other assets			45,771	12,702
Decrease in other liabilities			(3,386)	(33,201)
Net transfers with subsidiaries			202,825	(602)
Cash provided by operating activities			405,259	(4,287)
Investing activities:
Decrease in restricted cash			20,456	1,506
Decrease in loans, net			(96,003)	(83,510)
Reduction of other investments, net			(71)	(116)
Acquisition of property and equipment, net			(618)	(933)
Cash provided by investing activities			(76,236)	(83,053)
Financing activities:
(Decrease) increase in intercompany payable			619,138	10,682
Repayments on credit facilities, net				(7,057)
Borrowings under (repayments of) other borrowings			(42)	(38)
Cash used in financing activities			619,096	3,587
Increase (decrease) in cash and cash equivalents			948,119	(83,753)
Cash and cash equivalents as of beginning of period			252,012	265,977
Cash and cash equivalents as of end of period	1,200,131	182,224	1,200,131	182,224
Other Non Guarantor Subsidiaries [Member]
Operating activities:
Net income (loss)	32,482	20,358	57,871	(176,677)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Amortization of deferred loan fees and discounts			(5,936)	(6,625)
Paid-in-kind interest on loans			(395)	846
Provision for loan losses	(1,559)	37,268	3,844	169,868
Amortization of deferred financing fees and discounts			(1,156)	4,098
Depreciation and amortization				1,441
Benefit for deferred income taxes			27,353	21,667
Non-cash (gain) loss on investments, net			(5,642)	(1,301)
Non-cash loss on foreclosed assets and other property and equipment disposals			6,471	46,487
Unrealized loss (gain) on derivatives and foreign currencies, net			5,426	22,966
Decrease in interest receivable			28,219	1,535
Decrease in loans held for sale, net			16,437	(7,468)
Decrease (increase) in intercompany receivable			(619,138)	(10,682)
Decrease (increase) in other assets			15,685	9,725
Decrease in other liabilities			(30,586)	34,886
Net transfers with subsidiaries			(45,584)	(253,307)
Cash provided by operating activities			(547,131)	(127,605)
Investing activities:
Decrease in restricted cash			3,967	(28,437)
Decrease in loans, net			435,131	286,618
Reduction (acquisition) of marketable securities, available for sale, net			19,000
Reduction of other investments, net			(2,515)	29,111
Cash received for real estate				339,643
Acquisition of property and equipment, net				859
Cash provided by investing activities			455,583	627,794
Financing activities:
Payment of deferred financing fees				4,172
(Decrease) increase in intercompany payable			(25,851)	10,105
Repayments on credit facilities, net			(1,902)	(33,882)
Borrowings of term debt				14,784
Repayments of term debt				(237,514)
Borrowings under (repayments of) other borrowings				(263,972)
Cash used in financing activities			(27,753)	(506,307)
Increase (decrease) in cash and cash equivalents			(119,301)	(6,118)
Cash and cash equivalents as of beginning of period			120,158	51,597
Cash and cash equivalents as of end of period	857	45,479	857	45,479
Consolidation, Eliminations [Member]
Operating activities:
Net income (loss)	(115,704)	(163,838)	(222,099)	54,348
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Decrease (increase) in intercompany receivable			551,153	23,345
Decrease (increase) in other assets			(18,601)	(24,917)
Decrease in other liabilities			13,334	21,910
Net transfers with subsidiaries			223,110	(58,012)
Cash provided by operating activities			546,897	16,674
Investing activities:
Decrease in loans, net			(460)	4,113
Cash provided by investing activities			(460)	4,113
Financing activities:
(Decrease) increase in intercompany payable			(546,437)	(20,787)
Cash used in financing activities			(546,437)	(20,787)
Cash and cash equivalents as of beginning of period			0	0
Cash and cash equivalents as of end of period	$ 0	$ 0	$ 0	$ 0