Deposits - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Interest-bearing demand	$ 1,926,019		$ 1,926,019		$ 1,720,383
Aggregate amount of certificates of deposit exceeding threshold amount	1,200,000		1,200,000		1,100,000
Interest expense on deposits	14,911	$ 15,250	31,743	$ 28,929
Stewardship Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Interest-bearing demand	$ 26,400		$ 26,400		$ 31,600