Carrying amount of loans accounted for pursuant to ASC310-30 (Detail) (Westernbank Puerto Rico [Member], Acquired Loans In An F D I C Assisted Transaction [Member], Covered Under Loss Sharing Agreements With F D I C [Member], A S C Subtopic 31030 [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	$ 2,528,433	$ 2,610,664	$ 2,827,947	$ 2,891,049	$ 3,012,866	$ 3,491,759
Less: Allowance for loan losses	(85,640)		(93,915)	(108,874)
Carrying amount, net of allowance	2,442,793		2,734,032	2,782,175
Commercial Real Estate Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	1,540,615		1,632,672
Commercial And Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	56,585		58,261
Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	69,404		176,220
Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	833,217		922,361
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	28,612		38,433
Performing Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	2,326,604	2,387,911	2,509,075	2,555,606	2,653,071	3,051,964
Less: Allowance for loan losses	(52,812)		(57,594)	(49,744)
Carrying amount, net of allowance	2,273,792		2,451,481	2,505,862
Performing Financing Receivable Member | Commercial Real Estate Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	1,425,288		1,483,331
Performing Financing Receivable Member | Commercial And Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	54,325		55,192
Performing Financing Receivable Member | Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	35,020		71,864
Performing Financing Receivable Member | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	784,898		862,878
Performing Financing Receivable Member | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	27,073		35,810
Nonperforming Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	201,829	222,753	318,872	335,443	359,795	439,795
Less: Allowance for loan losses	(32,828)		(36,321)	(59,130)
Carrying amount, net of allowance	169,001		282,551	276,313
Nonperforming Financing Receivable Member | Commercial Real Estate Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	115,327		149,341
Nonperforming Financing Receivable Member | Commercial And Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	2,260		3,069
Nonperforming Financing Receivable Member | Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	34,384		104,356
Nonperforming Financing Receivable Member | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	48,319		59,483
Nonperforming Financing Receivable Member | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount	$ 1,539		$ 2,623