Note Goodwill and other intangible assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite Lived Intangible Assets	$ 6,100		$ 6,100
Amortization Of Intangible Assets	2,345	$ 3,114
Goodwill Purchase Accounting Adjustments	0	4,707
Goodwil, Acquired During Period	$ 0	0
FDIC Assisted Partial Acquisition Of Doral Bank
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill Purchase Accounting Adjustments		4,700
Goodwil, Acquired During Period		$ 167,800