Equity Investments in Unconsolidated Subsidiaries - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jan. 31, 2011
Schedule of Equity Method Investments [Line Items]
Promote income recognized			$ 5,007,000	$ 14,125,000
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			$ 7,500,000
Promote income recognized	$ 17,000	$ 24,300,000	$ 5,700,000	24,300,000
Percentage of carried interest distributions pool for employees					45.00%
Percentage of pool vested	68.00%		68.00%
Description of incentive management fee grants to employees vesting schedule			Approximately 68% of the pool is two-thirds vested as of June 30, 2015, with the remainder contingent on continued employment with an affiliate of our Manager and upon our receipt of promote distributions from CTOPI. The remaining 32% of the pool is fully vested as a result of an acceleration event. During the six months ended June 30, 2015, we accrued $2.5 million under the CTOPI incentive plan, which amount was recognized as a component of general and administrative expenses in our consolidated statement of operations.
CT Opportunity Partners I, LP [Member] | CTOPI Incentive Plan [Member]
Schedule of Equity Method Investments [Line Items]
Accrued expenses for incentive plan	$ 8,000	$ 11,200,000	$ 2,600,000	$ 11,200,000
CT Opportunity Partners I, LP [Member] | Acceleration Event [Member]
Schedule of Equity Method Investments [Line Items]
Fully vested pool, percentage	32.00%		32.00%