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Acquisition of Stewardship Financial Corporation - Narrative (Details) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
	Nov. 01, 2019 USD ($) branch $ / shares	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2017 USD ($)
Business Acquisition [Line Items]
Assets			$ 8,188,694	$ 6,691,618
Loans receivable, net			6,135,857	4,916,840
Liabilities			7,206,177	5,719,558
Deposits			5,645,842	4,413,873
Borrowings			1,407,022	1,189,180
Merger-related expenses		$ 0	2,755	0	$ 0
Goodwill			60,763	$ 5,716
Stewardship Financial Corporation
Business Acquisition [Line Items]
Business acquisition, share price (in dollars per share) \| $ / shares	$ 15.75
Merger-related expenses			$ 2,800
Goodwill	$ 55,047
Stewardship Financial Corporation
Business Acquisition [Line Items]
Assets	956,000
Loans receivable, net	756,900
Securities	52,600
Liabilities	877,800
Deposits	781,400
Borrowings	$ 81,800
Number of stores \| branch	12
Core Deposits \| Stewardship Financial Corporation
Business Acquisition [Line Items]
Core deposit intangible	$ 7,500
Acquired finite-lived intangible assets, weighted average useful life	10 years
Leasehold Improvements And Equipment \| Minimum \| Stewardship Financial Corporation
Business Acquisition [Line Items]
Property, plant and equipment, useful life	3 years
Leasehold Improvements And Equipment \| Maximum \| Stewardship Financial Corporation
Business Acquisition [Line Items]
Property, plant and equipment, useful life	10 years