Stockholders' Equity - Summary of Line Item Affected by Amounts Reclassified from Accumulated Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Comprehensive Income Loss Amount Reclassified From Accumulated Other Comprehensive Income [Abstract]
Amortization/accretion of unrealized net gain/(loss) on securities transferred to HTM	$ 892	$ (1,456)	$ 2,463	$ (7,099)
Tax effect			879	(2,563)
Net of tax			1,584	(4,536)
Amortization of defined benefit pension and post-retirement items			293	5,534
Tax effect			103	2,070
Net of tax			190	3,464
Gains and losses on cash flow hedges				301
Tax effect				105
Net of tax				196
Total reclassifications, net of tax			$ 1,774	$ (876)