Notes Payable, Collateralized and Short-Term Borrowings - Summary of Interest Expense Related to Company's Convertible Notes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Debt Instrument [Line Items]
Amortization of discount	$ (628)	$ (1,316)
4.50% Convertible Notes [Member]
Debt Instrument [Line Items]
Coupon interest		1,800
Amortization of discount		1,225
Total interest expense		$ 3,025