Recently Issued Accounting Pronouncements - Summary of Additional Funding to Investments (Detail) $ in Thousands	Sep. 30, 2015 USD ($)
Investments, All Other Investments [Abstract]
Equity commitments in 2015	$ 8,251
Equity commitments in 2016	4,148
Equity commitments in 2017	1,314
Equity commitments in 2018	726
Equity commitments in 2019	1,078
Total Equity commitments	$ 15,517