Servicing of Residential Loans - Schedule of Geographic Diversification of Third-Party Servicing Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2013 Accounts	Dec. 31, 2012 Accounts
Servicing Rights [Line Items]
Total servicing portfolio, Number of Accounts	1,960,270	1,038,981
Total servicing portfolio, Unpaid Principal Balance	$ 211,226,362	$ 90,094,189
Third-party investors [Member]
Servicing Rights [Line Items]
Total servicing portfolio, Number of Accounts	1,848,981	945,260
Total servicing portfolio, Unpaid Principal Balance	200,026,907	82,113,522
Total servicing portfolio, Percentage of Total	100.00%	100.00%
Third-party investors [Member] | CALIFORNIA
Servicing Rights [Line Items]
Total servicing portfolio, Number of Accounts	204,981	81,547
Total servicing portfolio, Unpaid Principal Balance	34,764,523	16,073,080
Total servicing portfolio, Percentage of Total	17.40%	19.60%
Third-party investors [Member] | FLORIDA
Servicing Rights [Line Items]
Total servicing portfolio, Number of Accounts	169,573	91,318
Total servicing portfolio, Unpaid Principal Balance	20,802,584	10,476,321
Total servicing portfolio, Percentage of Total	10.40%	12.80%
Third-party investors [Member] | TEXAS
Servicing Rights [Line Items]
Total servicing portfolio, Number of Accounts	144,367	86,406
Total servicing portfolio, Unpaid Principal Balance	10,435,713	3,621,528
Total servicing portfolio, Percentage of Total	5.20%	4.40%
Third-party investors [Member] | Other less than 5% [Member]
Servicing Rights [Line Items]
Total servicing portfolio, Number of Accounts	1,330,060	685,989
Total servicing portfolio, Unpaid Principal Balance	$ 134,024,087	$ 51,942,593
Total servicing portfolio, Percentage of Total	67.00%	63.20%