Notes Payable, Collateralized and Short-Term Borrowings - Notes Payable, Collateralized and Short-Term Borrowings (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	May 27, 2016	Dec. 09, 2014	Jun. 26, 2012
Debt Instrument [Line Items]
Notes payable, collateralized and short-term borrowings	$ 1,140,887	$ 965,767
8.125% Senior Notes [Member]
Debt Instrument [Line Items]
Notes payable, collateralized and short-term borrowings	109,334	109,271			$ 108,700
5.375% Senior Notes [Member]
Debt Instrument [Line Items]
Notes payable, collateralized and short-term borrowings	297,573	297,083		$ 295,100
8.375% Senior Notes [Member]
Debt Instrument [Line Items]
Notes payable, collateralized and short-term borrowings	244,750	246,988
5.125% Senior Notes [Member]
Debt Instrument [Line Items]
Notes payable, collateralized and short-term borrowings	296,600	296,215	$ 295,800
Collateralized Borrowings [Member]
Debt Instrument [Line Items]
Notes payable, collateralized and short-term borrowings	42,630	$ 16,210
Short-term Borrowings [Member]
Debt Instrument [Line Items]
Notes payable, collateralized and short-term borrowings	$ 150,000