Equity Investments in Unconsolidated Subsidiaries - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2012	Jan. 31, 2011
Schedule of Equity Method Investments [Line Items]
Distributions		$ 1,006,000
Income from equity investments in unconsolidated subsidiaries	28,036,000	1,781,000
CT Opportunity Partners I, LP [Member]
Schedule of Equity Method Investments [Line Items]
Carried interest revenue, percentage of fund's profit	17.70%
Preferred return	9.00%
Return of capital to partners	100.00%
Carried interest revenue	10,600,000
Distributions	17,900,000
Advance distribution of carried interest revenue	10,200,000
Income from equity investments in unconsolidated subsidiaries	28,000,000
Percentage of carried interest distributions pool for employees			45.00%
Percentage of granted carried interest distributions to employees	96.00%
Percentage of grants vesting schedule	65.00%
Percentage of grants vesting upon receipt of dividends	35.00%
Description of incentive management fee grants to employees vesting schedule	(i) one-third on the date of grant; (ii) one-third on September 13, 2012; and (iii) the remainder is contingent on continued employment with an affiliate of our Manager and upon our receipt of carried interest distributions from CTOPI. Of the remaining 35% of these grants, 31% are fully vested as a result of an acceleration event, and 4% vest solely upon our receipt of carried interest distributions from CTOPI or the disposition of certain investments owned by CTOPI.
Payment under equity method investment	$ 12,900,000
CT Opportunity Partners I, LP [Member] | Acceleration Event [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of grants vesting upon receipt of dividends	31.00%
CT Opportunity Partners I, LP [Member] | Incentive Management Fees [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of grants vesting upon receipt of dividends	4.00%