Balance Sheet Offsetting - Gross Presentation Effects of Offsetting and Net Presentation of Valley's Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Derivatives And Hedging Activities [Line Items]
Gross Amounts Recognized, Total	$ 442,068	$ 428,239
Gross Amounts Offset, Total	0	0
Net Amounts Presented, Total	442,068	428,239
Net Amount, Total	0	0
Interest Rate Caps and Swaps, Assets [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Recognized, Assets	29,728	20,950
Gross Amounts Offset, Assets	0	0
Net Amounts Presented, Assets	29,728	20,950
Gross Amounts Not Offset, Assets	18,869	12,446
Interest Rate Caps and Swaps, Liabilities [Member]
Derivatives And Hedging Activities [Line Items]
Net Amount, Total	0	0
Gross Amounts Recognized, Liabilities	47,068	33,239
Gross Amounts Offset, Liabilities	0	0
Net Amounts Presented, Liabilities	47,068	33,239
Repurchase Agreements [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Recognized, Liabilities	395,000	395,000
Gross Amounts Offset, Liabilities	0	0
Net Amounts Presented, Liabilities	395,000	395,000
Net Amount, Liabilities	0	0
Financial Instruments [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Not Offset, Total	(10,859)	(8,504)
Financial Instruments [Member] | Interest Rate Caps and Swaps, Assets [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Not Offset, Assets	(10,859)	(8,504)
Financial Instruments [Member] | Interest Rate Caps and Swaps, Liabilities [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Not Offset, Liabilities	(10,859)	(8,504)
Cash Collateral [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Not Offset, Total	431,209	419,735
Cash Collateral [Member] | Interest Rate Caps and Swaps, Assets [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Not Offset, Assets	0
Cash Collateral [Member] | Interest Rate Caps and Swaps, Liabilities [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Not Offset, Liabilities	(36,209)	(24,735)
Cash Collateral [Member] | Repurchase Agreements [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amounts Not Offset, Liabilities	$ (395,000)	$ (395,000)