Investments - Investments in Variable Interest Entities (Detail) - Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] - USD ($)		Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Investment	[1]	$ 4,503,000	$ 3,899,000
Maximum Exposure to Loss	[1]	$ 5,483,000	$ 4,879,000

[1] The Company has entered into a subordinated loan agreement with Aqua, whereby the Company agreed to lend the principal sum of $980.0 thousand. The Company’s maximum exposure to loss with respect to its unconsolidated VIEs includes the sum of its equity investments in its unconsolidated VIEs and the $980.0 thousand subordinated loan to Aqua.