Deposits - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Interest-bearing demand	$ 2,033,729		$ 2,033,729		$ 1,720,383
Aggregate amount of certificates of deposit exceeding threshold amount	1,100,000		1,100,000		1,100,000
Interest expense on deposits	12,826	$ 16,055	44,569	$ 44,984
Stewardship Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Interest-bearing demand	$ 26,400		$ 26,400		$ 31,600