Note Goodwill and other intangible assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite Lived Intangible Assets	$ 6,100		$ 6,100		$ 6,100
Amortization Of Intangible Assets	$ 2,344	$ 3,097	4,689	$ 6,211
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