Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Allowance for loan losses	$ 32,353	$ 36,514
Stock-based compensation	17,746	19,270
Net actuarial loss on defined benefit post-retirement benefit plans	14,070	26,423
Bonus accrual	5,301	5,006
Gain on sale of assets	2,234	2,329
Partnerships	2,208	1,808
Non-accrual loans	977	1,719
Other	4,077	4,014
Total gross deferred tax assets	78,966	97,083
Net unrealized gain on securities available for sale and effective cash flow hedging derivatives	(89,689)	(154,603)
Premises and equipment	(21,192)	(22,451)
Defined benefit post-retirement benefit plans	(14,137)	(14,895)
Intangible assets	(7,253)	(6,924)
Leases	(4,237)	(4,717)
Bonus accrual 481(a) adjustment	(1,091)	(2,182)
Prepaid expenses	(1,618)	(1,516)
Reserve for medical insurance	(2,171)	(1,509)
Other	(365)	(355)
Total gross deferred tax liabilities	(141,753)	(209,152)
Net deferred tax asset (liability)	$ (62,787)	$ (112,069)