Goodwill and Other Intangible Assets - Carrying Amount of Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Goodwill [Line Items]
Beginning balance	$ 317,962		$ 317,891
Goodwill from business combinations	110,272		71
Ending balance	428,234		317,962
Wealth Management [Member]
Goodwill [Line Items]
Beginning balance	20,517	[1]	20,446	[1]
Goodwill from business combinations		[1]	71	[1]
Ending balance	20,517	[1]	20,517	[1]
Consumer loans [Member]
Goodwill [Line Items]
Beginning balance	98,999		98,999
Goodwill from business combinations	29,452
Ending balance	128,451		98,999
Commercial loans [Member]
Goodwill [Line Items]
Beginning balance	117,689		117,689
Goodwill from business combinations	57,074
Ending balance	174,763		117,689
Investment Management [Member]
Goodwill [Line Items]
Beginning balance	80,757		80,757
Goodwill from business combinations	23,746
Ending balance	$ 104,503		$ 80,757

[1] Valley's Wealth Management Division is comprised of trust, asset management, and insurance services. This reporting unit is included in the Consumer Lending segment for financial reporting purposes.