Details of Retention and Purchase of MSRs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Mortgage Servicing Rights [Line Items]
MSR Fair Value			$ 30,962	$ 41,128
Mortgage Servicing Rights
Mortgage Servicing Rights [Line Items]
MSR Fair Value	61,606	16,676	76,272	45,291
Associated Principal	5,365,350		6,835,123
Mortgage Servicing Rights \| Jumbo MSR Additions
Mortgage Servicing Rights [Line Items]
MSR Fair Value	4,356		7,030
Associated Principal	516,004		831,998
Mortgage Servicing Rights \| Jumbo MSR Additions \| Securitization
Mortgage Servicing Rights [Line Items]
MSR Fair Value	4,356		6,542
Associated Principal	516,004		773,205
Mortgage Servicing Rights \| Jumbo MSR Additions \| Loan Sales
Mortgage Servicing Rights [Line Items]
MSR Fair Value			488
Associated Principal			58,793
Mortgage Servicing Rights \| Conforming MSR Additions
Mortgage Servicing Rights [Line Items]
MSR Fair Value	57,250		69,242
Associated Principal	4,849,346		6,003,125
Mortgage Servicing Rights \| Conforming MSR Additions \| Loan Sales
Mortgage Servicing Rights [Line Items]
MSR Fair Value	14,630		23,933
Associated Principal	1,352,122		2,232,559
Mortgage Servicing Rights \| Conforming MSR Additions \| From purchases
Mortgage Servicing Rights [Line Items]
MSR Fair Value	42,620		45,309
Associated Principal	$ 3,497,224		$ 3,770,566