Special Purpose Entities, Including Variable Interest Entities - Supplemental Information about Loans Held as Assets and Long-Term Debt Associated with Consolidated Variable Interest Entities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Variable Interest Entities [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 13,631,197	$ 13,235,425
Variable Interest Entities [Member] | Successor [Member]
Variable Interest Entities [Line Items]
Loans, Estimated fair value	11,015,305	10,658,963
Long-term debt, Estimated fair value	11,564,054	11,155,936
Loans, Unpaid principal balance	7,726,235	7,641,756
Long-term debt, Unpaid principal balance	$ 8,960,947	$ 8,854,530