Balance Sheet Offsetting - Gross Presentation Effects of Offsetting and Net Presentation of Valley's Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Offsetting Liabilities
Gross Amounts Recognized, Total Liabilities	$ 418,628	$ 525,752
Gross Amounts Offset, Total Liabilities	0	0
Net Amounts Presented, Total Liabilities	418,628	525,752
Gross Amounts Not Offset, Financial Instruments	(14,991)	(8,942)
Gross Amounts Not Offset, Cash Collateral	(403,637)	(516,810)
Net Amount, Total	0	0
Repurchase Agreements
Offsetting Liabilities
Gross Amounts Recognized, Liabilities	340,000	475,000
Gross Amounts Offset, Liabilities	0	0
Net Amounts Presented, Liabilities	340,000	475,000
Gross Amounts Not Offset, Liabilities	0	0
Gross Amounts Not Offset, Liabilities	(340,000)	(475,000)
Net Amount, Liabilities	0	0
Interest Rate Caps and Swaps
Offsetting Assets
Gross Amounts Recognized, Assets	59,851	33,570
Gross Amounts Offset, Assets	0	0
Net Amounts Presented, Assets	59,851	33,570
Gross Amounts Not Offset, Financial Instruments	(14,991)	(8,942)
Gross Amounts Not Offset, Cash Collateral	0	0
Net Amount, Assets	44,860	24,628
Offsetting Liabilities
Gross Amounts Recognized, Liabilities	78,628	50,752
Gross Amounts Offset, Liabilities	0	0
Net Amounts Presented, Liabilities	78,628	50,752
Gross Amounts Not Offset, Financial Instruments	(14,991)	(8,942)
Gross Amounts Not Offset, Cash Collateral	(63,637)	(41,810)
Net Amount, Liabilities	$ 0	$ 0