Non-consolidated variable interest entities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		3 Months Ended
	Sep. 30, 2011 Prlp2011 Holdings Llc Joint Venture [Member]	Sep. 30, 2014 Prlp2011 Holdings Llc Joint Venture [Member]	Mar. 31, 2013 PR Asset Portfolio 2013-1 International, LLC [Member]	Sep. 30, 2014 PR Asset Portfolio 2013-1 International, LLC [Member]	Mar. 31, 2013 PR Asset Portfolio 2013-1 International, LLC [Member] Unpaid Principal Balance of Loans and Appraisal Value of OREO	Mar. 31, 2013 PR Asset Portfolio 2013-1 International, LLC [Member] Nonperforming Financing Receivable Member	Sep. 30, 2014 Fnma Gnma Fhlmc Vie [Member]	Dec. 31, 2013 Fnma Gnma Fhlmc Vie [Member]
Variable Interest Entity [Line Items]
Principal Amount Outstanding on Loans Securitized or Asset-backed Financing Arrangement							$ 9,000	$ 9,200
Equity Method Investment Ownership Percentage	24.90%	24.90%	24.90%	24.90%
Equity Method Investment, Underlying Equity in Net Assets	16		31
Loans Receivable, Description of Variable Rate Basis	5-year maturity and bears a variable interest at 30-day LIBOR plus 300 basis points		5-year maturity and bears a variable interest at 30-day LIBOR plus 300 basis points
Variable Interest Entity, Qualitative or Quantitative Information, Size of VIE	In September of 2011, BPPR sold construction and commercial real estate loans with a fair value of $148 million		On March 25, 2013, BPPR completed a sale of assets with a book value of $509.0 million, of which $500.6 million were in non-performing status
Purchase Price Of Loans	57.00%		57.00%
Financed Closing Costs	2
Carrying Amount Of Acquisition Loan Before Financed Closing Costs	84
Carrying Amount Of Acquisition Loan After Financed Closing Costs	86.0		182.4
Total Working Capital Line	20.0		30.0
Total Advance Facility	68.5		35.0
Cash Received From Investee	48.0		92.3
Net Equity Of Investee	63		124
Fair Value Of Assets Sold	148		306
Assets Sold			$ 509.0		$ 987.0	$ 500.6