Note Loans (Carrying amount of Westernbank loans accounted for pursuant to ASC310-30) (Detail) - Westernbank Puerto Rico - Acquired loans in an FDIC assisted transaction - ASC Subtopic 310-30 - USD ($) $ in Thousands	Mar. 31, 2018		Dec. 31, 2017		Mar. 31, 2017		Dec. 31, 2016	[1]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	$ 1,575,143	[1],[2]	$ 1,592,921	[2]	$ 1,688,900	[1],[2]	$ 1,738,329
Less: Allowance for loan losses	(89,763)		(70,129)		(66,544)
Carrying amount, net of allowance	1,485,380		1,522,792		1,622,356
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	911,715		923,424
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	86,447		88,130
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	170		170
Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	559,957		563,539
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	16,854		17,658
Non-credit Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	1,539,067	[1],[2]	1,556,601	[2]	1,648,328	[1],[2]	1,695,381
Less: Allowance for loan losses	(84,801)		(64,520)		(59,283)
Carrying amount, net of allowance	1,454,266		1,492,081		1,589,045
Non-credit Impaired Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	898,172		909,389
Non-credit Impaired Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	86,447		88,130
Non-credit Impaired Loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	0		0
Non-credit Impaired Loans | Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	538,352		542,182
Non-credit Impaired Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	16,096		16,900
Credit Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	36,076	[1],[2]	36,320	[2]	40,572	[1],[2]	$ 42,948
Less: Allowance for loan losses	(4,962)		(5,609)		(7,261)
Carrying amount, net of allowance	31,114		30,711		$ 33,311
Credit Impaired Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	13,543		14,035
Credit Impaired Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	0		0
Credit Impaired Loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	170		170
Credit Impaired Loans | Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	21,605		21,357
Credit Impaired Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	$ 758		$ 758

[1] The carrying amount of loans acquired from Westernbank and accounted for under ASC 310-30 which remain subject to the loss sharing agreement with the FDIC amounted to approximately $ 505 million as of March 31, 2018 (March 31, 2017- $542 million).

[2] The carrying amount of loans acquired from Westernbank and accounted for under ASC 310-30 which remains subject to the loss sharing agreement with the FDIC amounted to approximately $505 million as of March 31, 2018 and $563 million as of December 31, 2016.