Carrying amount and classification of assets related to the Corporation's variable interests in non-consolidated VIEs and maximum exposure to loss (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	$ 56,881	$ 81,181
Liabilities	(3,178)	(5,334)
Net assets	53,703	75,847
Variable Interest Entity Entity Maximum Loss Exposure Amount	53,703	75,847
PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	208,015
Liabilities	(13,284)
Net assets	194,731
Variable Interest Entity Entity Maximum Loss Exposure Amount	194,731
Fnma Gnma Fhlmc Vie [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	106,732	106,352
Variable Interest Entity Entity Maximum Loss Exposure Amount	106,732	106,352
Loan | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	23,936	45,090
Loan | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	137,792
Acquisition Loan [Member] | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	12,886	39,775
Acquisition Loan [Member] | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	136,997
Advances Working Capital Line [Member] | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	1,199	0
Advances Working Capital Line [Member] | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	795
Advances Advance Facility [Member] | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	9,851	5,315
Advances Advance Facility [Member] | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	0
Accrued Income Receivable [Member] | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	62	122
Accrued Income Receivable [Member] | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	85
Other Assets Member | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	32,883	35,969
Other Assets Member | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	70,138
Other Assets Member | Fnma Gnma Fhlmc Vie [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	1,164	1,106
Other Advances [Member] | Fnma Gnma Fhlmc Vie [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	1,164	1,106
Equity Method Investments [Member] | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	32,883	35,969
Equity Method Investments [Member] | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	70,138
Servicing Asset At Fair Value Amount [Member] | Fnma Gnma Fhlmc Vie [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	105,568	105,246
Mortgage Servicing Rights [Member] | Fnma Gnma Fhlmc Vie [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Assets	105,568	105,246
Deposits Member | Prlp2011 Holdings Llc Joint Venture [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Liabilities	(3,178)	(5,334)
Deposits Member | PR Asset Portfolio 2013-1 International, LLC [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Liabilities	$ (13,284)