Commitments and Contingencies - Summary of Maximum Exposure under Guarantee (Detail) - SAC [Member] $ in Thousands	Sep. 30, 2018 USD ($)
Loss Contingencies [Line Items]
Maximum guaranteed debt	$ 23,938
Equity investments	8,175	[1]
Maximum total exposure, including equity investments	$ 32,113

[1] Recorded in other assets on the Company’s consolidated condensed balance sheets.