Stockholders' equity - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Stockholders Equity Note [Line Items]
Puerto Rico Laws Restrictions On Banks Net Income		a minimum of 10% of BPPR’s net income
Equity Restrictions		$ 415,000,000		$ 415,000,000
Transfers To Statutory Reserve		$ 0	$ 0
Common Stock Shares Authorized		170,000,000		170,000,000
Stockholders' Equity, Reverse Stock Split	On May 29, 2012, the Corporation effected a 1-for-10 reverse split of its common stock previously approved by the Corporation’s stockholders on April 27, 2012. Upon the effectiveness of the reverse split, each 10 shares of authorized and outstanding common stock were reclassified and combined into one new share of common stock. Popular, Inc.’s common stock began trading on a split-adjusted basis on May 30, 2012. All share and per share information in the consolidated financial statements and accompanying notes have been retroactively adjusted to reflect the 1-for-10 reverse stock split.
Stockholders Equity Reverse Stock Split Conversion Ratio		1-for-10
Common Stock Shares Authorized Before Reverse				1,700,000,000