Stockholders' equity - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Stockholders Equity Note [Line Items]
Puerto Rico Laws Restrictions On Banks Net Income		a minimum of 10% of BPPR’s net income
Equity Restrictions	$ 445,000,000	$ 445,000,000		$ 445,000,000
Transfers To Statutory Reserve		0	0
Investment Warrants	$ 67
Payments For Repurchase Of Warrants		(3,000,000)	0
Warrant Expiration Term	10 years 0 months 0 days
Warrant [Member]
Stockholders Equity Note [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,093,284
Additional Paid In Capital Member
Stockholders Equity Note [Line Items]
Payments For Repurchase Of Warrants		$ (3,000,000)