Equity Investment in Unconsolidated Subsidiary - Additional Information (Detail) - CT Opportunity Partners I, LP [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jan. 31, 2011
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%
Promote income recognized	$ 2.1		$ 2.2
Percentage of carried interest distributions pool for employees				45.00%
Description of incentive management fee grants to employees vesting schedule		During the nine months ended September 30, 2016, we recognized $1.1 million of expenses under the CTOPI incentive plan. Such amounts were recognized as a component of general and administrative expenses in our consolidated statement of operations.
CTOPI Incentive Plan [Member]
Schedule of Equity Method Investments [Line Items]
Recognized expenses for incentive plan			$ 1.1