Note FDIC loss-share asset and true-up payment obligation (FDIC loss share - Additional Information) (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	May 22, 2018	Mar. 31, 2018	Dec. 31, 2018
Business Acquisition, Contingent Consideration
Payment to the FDIC as a consideration for the termination of the loss share agreement.	$ 23,700
Carrying amount (fair value)		$ 171,000	$ 165,000
FDIC loss-share asset net		44,469
Gain from the FDIC termination agreement			$ 102,800
Non-covered loans | Mortgages
Business Acquisition, Contingent Consideration
OREO transfer to non-covered status		15,300
Loans transfer to non-covered status		$ 514,600
Banco Popular de Puerto Rico
Business Acquisition, Contingent Consideration
Loss Sharing Agreement Allocation Percentage	80.00%