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, 2016	Dec. 31, 2015
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$ 1,724	$ 1,483
Less than 12 months Gross Unrealized Losses	26	17
12 months or more Fair Value	31,393	33,334
12 months or more Gross Unrealized Losses	23,547	21,606
Total Fair Value	33,117	34,817
Total Gross Unrealized Losses	23,573	21,623
Obligations of Puerto Rico, States and political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	0	0
Less than 12 months Gross Unrealized Losses	0	0
12 months or more Fair Value	31,393	33,334
12 months or more Gross Unrealized Losses	23,547	21,606
Total Fair Value	31,393	33,334
Total Gross Unrealized Losses	23,547	21,606
Other
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	1,724	1,483
Less than 12 months Gross Unrealized Losses	26	17
12 months or more Fair Value	0	0
12 months or more Gross Unrealized Losses	0	0
Total Fair Value	1,724	1,483
Total Gross Unrealized Losses	$ 26	$ 17