Variable Interest Entities - Summary of Carrying Amounts of Assets and Liabilities Related to Variable Interests (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]
Servicing Rights, Net	$ 193,833	$ 205,042	$ 216,330
Servicer and protective advances, net	1,044,410		173,047
VIE Not Primary Beneficiary [Member] | Servicing Arrangements with Loc Reimbursement Obligation [Member]
Variable Interest Entity [Line Items]
Servicing Rights, Net	2,075		2,319
Servicer and protective advances, net	2,631		2,691
Total	4,706		5,010
Maximum Exposure to Loss	169,706		170,010
Unpaid Principal Balance of Transferred Loans	$ 210,362		$ 223,251