Summarized Quarterly Results (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011
Quarterly Results [Line Items]
Net portfolio interest income	$ 600	$ 1,061	$ 976	$ 1,165	$ 981	$ 1,081	$ 1,231	$ 1,523
Interest on junior subordinated notes	257	266	261	265	258	250	250	250
Other portfolio gains (losses)	(1,073)	(19)	(1,516)	(459)	(418)	(2,801)	1,032	248
Net portfolio income (loss)	(730)	776	(801)	441	305	(1,970)	2,013	1,521
Other (loss) income	119	796	1,751	1,694	(716)	2,436	1,487	(82)
Expenses	1,305	2,334	1,141	1,296	1,996	2,379	1,291	1,950
Net (loss) income	$ (1,916)	$ (762)	$ (191)	$ 839	$ (2,407)	$ (1,913)	$ 2,209	$ (511)
[CommonClassAMember]
Earnings Per Share [Abstract]
Basic	$ (0.18)	$ (0.07)	$ (0.02)	$ 0.08	$ (0.24)	$ (0.19)	$ 0.22	$ (0.05)
Diluted	$ (0.18)	$ (0.07)	$ (0.02)	$ 0.08	$ (0.24)	$ (0.19)	$ 0.22	$ (0.05)
[CommonClassBMember]
Earnings Per Share [Abstract]
Basic	$ (0.18)	$ (0.07)	$ (0.02)	$ 0.08	$ (0.24)	$ (0.19)	$ 0.22	$ (0.05)
Diluted	$ (0.18)	$ (0.07)	$ (0.02)	$ 0.08	$ (0.24)	$ (0.19)	$ 0.22	$ (0.05)