Borrowed Funds - Scheduled FHLB Advances (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Due in one year or less	$ 250,166
Due after one year through two years	277,318
Due after two years through three years	290,010
Due after three years through four years	314,334
Due after four years through five years	188,454
Thereafter	30,000
Total FHLB advances	$ 1,350,282	$ 1,190,280
Minimum [Member]
Debt Instrument [Line Items]
Maturity date of FHLB advances	Jan. 31, 2016
Maximum [Member]
Debt Instrument [Line Items]
Maturity date of FHLB advances	Apr. 30, 2022