Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassification Out Of Accumulated Other Comprehensive Loss [LineItems]
Interest and dividends on investment	$ 198	$ 113
Interest expense	(39,014)	(42,997)
Amortization of prior service cost	0	(1,987)
Amounts Reclassified from Accumulated Other Comprehensive Loss, tax effect	(830)	(12,814)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Out Of Accumulated Other Comprehensive Loss [LineItems]
Interest expense	(1,648)	(1,880)
Amounts Reclassified from Accumulated Other Comprehensive Loss, net of tax	(892)	696
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized Gains and Losses on Available for Sale (AFS) Securities [Member]
Reclassification Out Of Accumulated Other Comprehensive Loss [LineItems]
Gains on securities transactions, net	(8)	3,958
Amounts Reclassified from Accumulated Other Comprehensive Loss, tax effect	3	(1,659)
Amounts Reclassified from Accumulated Other Comprehensive Loss, net of tax	(5)	2,299
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Non-Credit Impairment Losses on AFS Securities [Member]
Reclassification Out Of Accumulated Other Comprehensive Loss [LineItems]
Interest and dividends on investment	198	113
Amounts Reclassified from Accumulated Other Comprehensive Loss, tax effect	(83)	(47)
Amounts Reclassified from Accumulated Other Comprehensive Loss, net of tax	115	66
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized Losses on Derivatives (Cash Flow Hedges) Before Tax [Member]
Reclassification Out Of Accumulated Other Comprehensive Loss [LineItems]
Interest expense	(1,648)	(1,880)
Amounts Reclassified from Accumulated Other Comprehensive Loss, tax effect	683	789
Amounts Reclassified from Accumulated Other Comprehensive Loss, net of tax	(965)	(1,091)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Defined Benefit Pension Plans [Member]
Reclassification Out Of Accumulated Other Comprehensive Loss [LineItems]
Amortization of prior service cost	0	(202)
Amortization of net actuarial loss	(62)	(794)
Total before tax	(62)	(996)
Amounts Reclassified from Accumulated Other Comprehensive Loss, tax effect	25	418
Amounts Reclassified from Accumulated Other Comprehensive Loss, net of tax	$ (37)	$ (578)