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, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entities [Line Items]
Loans, Unpaid principal balance	$ 6,936	$ 7,734
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	15,085,685	15,872,770
Variable Interest Entities [Member] | Successor [Member]
Variable Interest Entities [Line Items]
Loans, Estimated fair value	12,371,177	13,398,895
Long-term debt, Estimated fair value	12,882,076	14,091,753
Loans, Unpaid principal balance	10,236,695	12,226,481
Long-term debt, Unpaid principal balance	$ 11,925,499	$ 14,251,771