Servicing of Residential Loans - Schedule of Total Servicing Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015 Accounts	Dec. 31, 2014 Accounts
Servicing Portfolio [Line Items]
Total servicing portfolio, Number of Accounts	2,274,052	2,309,648
Total servicing portfolio, Unpaid Principal Balance	$ 255,081,992	$ 256,112,142
Third-party Investors [Member]
Servicing Portfolio [Line Items]
Total servicing portfolio, Number of Accounts	2,155,926	2,192,885
Total servicing portfolio, Unpaid Principal Balance	242,204,750	243,532,675
Third-party Investors [Member] | Capitalized Servicing Rights [Member]
Servicing Portfolio [Line Items]
Total servicing portfolio, Number of Accounts	1,557,666	1,573,867
Total servicing portfolio, Unpaid Principal Balance	182,404,047	182,207,043
Third-party Investors [Member] | Capitalized Sub-servicing [Member]
Servicing Portfolio [Line Items]
Total servicing portfolio, Number of Accounts	181,185	187,747
Total servicing portfolio, Unpaid Principal Balance	10,116,134	10,443,480
Third-party Investors [Member] | Sub-servicing [Member]
Servicing Portfolio [Line Items]
Total servicing portfolio, Number of Accounts	417,075	431,271
Total servicing portfolio, Unpaid Principal Balance	49,684,569	50,882,152
On-balance Sheet [Member] | Residential Loans and Real Estate Owned [Member]
Servicing Portfolio [Line Items]
Total servicing portfolio, Number of Accounts	118,126	116,763
Total servicing portfolio, Unpaid Principal Balance	$ 12,877,242	$ 12,579,467