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	Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entities [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 15,473,572	$ 15,085,685
Variable Interest Entities [Member] | Successor [Member]
Variable Interest Entities [Line Items]
Loans, Estimated fair value	12,789,201	12,371,177
Long-term debt, Estimated fair value	13,341,902	12,882,076
Loans, Unpaid principal balance	9,675,140	10,236,695
Long-term debt, Unpaid principal balance	$ 11,299,861	$ 11,925,499