Note Investment Securities Held-to-maturity (HTM securities in a continuous unrealized loss position) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$ 32,263	$ 31,785
Less than 12 months Gross Unrealized Losses	1,777	1,711
12 months or more Fair Value	29,928	32,164
12 months or more Gross Unrealized Losses	22,312	22,186
Total Fair Value	62,191	63,949
Total Gross Unrealized Losses	24,089	23,897
Obligations of Puerto Rico, States and political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	31,526	31,294
Less than 12 months Gross Unrealized Losses	1,764	1,702
12 months or more Fair Value	28,703	30,947
12 months or more Gross Unrealized Losses	22,287	22,153
Total Fair Value	60,229	62,241
Total Gross Unrealized Losses	24,051	23,855
Other
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	737	491
Less than 12 months Gross Unrealized Losses	13	9
12 months or more Fair Value	1,225	1,217
12 months or more Gross Unrealized Losses	25	33
Total Fair Value	1,962	1,708
Total Gross Unrealized Losses	$ 38	$ 42