Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net income (loss):
Net income (loss) from continuing operations	$ 16,594	$ (5,522)	$ 19,753	$ (224,535)
Net income from discontinued operations, net of taxes		2,166		9,489
Net gain from sale of discontinued operations, net of taxes		21,696		21,696
Total from discontinued operations		23,862		31,185
Net income (loss) attributable to CapitalSource Inc.	$ 16,594	$ 18,340	$ 19,753	$ (193,350)
Average shares - basic	320,426,484	320,802,358	320,311,588	320,547,818
Effect of dilutive securities:
Option shares	2,003,029		2,261,172
Unvested restricted stock	4,658,204		4,452,828
Average shares - diluted	327,087,717	320,802,358	327,025,588	320,547,818
Basic net income (loss) per share:
From continuing operations	$ 0.05	$ (0.02)	$ 0.06	$ (0.70)
From discontinued operations, net of taxes		$ 0.08		$ 0.10
Net income (loss) per share	$ 0.05	$ 0.06	$ 0.06	$ (0.60)
Diluted net income (loss) per share:
From continuing operations	$ 0.05	$ (0.02)	$ 0.06	$ (0.70)
From discontinued operations, net of taxes		$ 0.08		$ 0.10
Net income (loss) per share	$ 0.05	$ 0.06	$ 0.06	$ (0.60)