Regulatory and Capital Requirements - Schedule of Actual Capital Positions and Ratios under Banking Regulations (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shareholders’ equity	$ 4,592,120	$ 4,384,188	$ 3,350,454	$ 2,533,165
Total Risk-based Capital
Risk-based capital actual, amount	$ 3,802,223	$ 3,427,134
Risk-based capital actual, ratio	0.1264	0.1172
Risk-based capital minimum capital requirements, amount	$ 3,159,019	$ 3,070,687
Risk-based capital minimum capital requirements, ratio	0.1050	0.1050
Common Equity Tier 1 Capital
Common equity tier 1 capital, amount	$ 2,991,085	$ 2,754,524
Common equity tier 1 capital, ratio	9.94%	9.42%
Common equity tier 1 capital minimum capital requirements, amount	$ 2,106,013	$ 2,047,125
Common equity tier 1 capital minimum capital requirements, ratio	7.00%	7.00%
Tier 1 Risk-based Capital
Tier 1 risk-based capital actual, amount	$ 3,205,926	$ 2,968,530
Tier 1 risk-based capital actual, ratio	0.1066	0.1015
Tier 1 risk-based capital minimum capital requirements, amount	$ 2,557,301	$ 2,485,795
Tier 1 risk-based capital minimum capital requirements, ratio	0.0850	0.0850
Tier 1 Leverage Capital
Tier 1 leverage capital actual, amount	$ 3,205,926	$ 2,968,530
Tier 1 leverage capital actual, ratio	0.0806	0.0876
Tier 1 leverage capital minimum capital requirements, amount	$ 1,591,852	$ 1,355,378
Tier 1 leverage capital minimum capital requirements, ratio	0.0400	0.0400
Retained Earnings
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shareholders’ equity	$ 611,158	$ 443,559	$ 299,642	$ 216,733
Cumulative Effect, Period of Adoption, Adjustment
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shareholders’ equity		(28,187)
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shareholders’ equity		(28,187)
Valley National Bank
Total Risk-based Capital
Risk-based capital actual, amount	$ 3,839,922	$ 3,416,674
Risk-based capital actual, ratio	0.1276	0.1169
Risk-based capital minimum capital requirements, amount	$ 3,158,842	$ 3,069,894
Risk-based capital minimum capital requirements, ratio	0.1050	0.1050
Risk-based capital to be well capitalized under prompt corrective action provision, amount	$ 3,008,421	$ 2,923,709
Risk-based capital to be well capitalized under prompt corrective action provision, ratio	0.1000	0.1000
Common Equity Tier 1 Capital
Common equity tier 1 capital, amount	$ 3,607,625	$ 3,152,070
Common equity tier 1 capital, ratio	11.99%	10.78%
Common equity tier 1 capital minimum capital requirements, amount	$ 2,105,894	$ 2,046,596
Common equity tier 1 capital minimum capital requirements, ratio	7.00%	7.00%
Common equity tier 1 capital to be well capitalized under prompt corrective action provision, amount	$ 1,955,473	$ 1,900,411
Common equity tier 1 capital to be well capitalized under prompt corrective action provision, ratio	6.50%	6.50%
Tier 1 Risk-based Capital
Tier 1 risk-based capital actual, amount	$ 3,607,625	$ 3,152,070
Tier 1 risk-based capital actual, ratio	0.1199	0.1078
Tier 1 risk-based capital minimum capital requirements, amount	$ 2,557,158	$ 2,485,153
Tier 1 risk-based capital minimum capital requirements, ratio	0.0850	0.0850
Tier 1 risk-based capital to be well capitalized under prompt corrective action provision, amount	$ 2,406,736	$ 2,338,967
Tier 1 risk-based capital to be well capitalized under prompt corrective action provision, ratio	0.0800	0.0800
Tier 1 Leverage Capital
Tier 1 leverage capital actual, amount	$ 3,607,625	$ 3,152,070
Tier 1 leverage capital actual, ratio	0.0907	0.0931
Tier 1 leverage capital minimum capital requirements, amount	$ 1,591,457	$ 1,354,693
Tier 1 leverage capital minimum capital requirements, ratio	0.0400	0.0400
Tier 1 leverage capital to be well capitalized under prompt corrective action provision, amount	$ 1,989,321	$ 1,693,366
Tier 1 leverage capital to be well capitalized under prompt corrective action provision, ratio	0.0500	0.0500