Loans - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($) contract	Sep. 30, 2018 USD ($) contract	Sep. 30, 2019 USD ($) contract	Sep. 30, 2018 USD ($) contract	Sep. 30, 2019 USD ($) contract	Sep. 30, 2018 USD ($) contract	Dec. 31, 2018 USD ($)
Receivables [Abstract]
Number of loans under trouble debt restructuring | contract	3	1	7	1	3	1
Value of loans under trouble debt restructuring	$ 1,600	$ 100	$ 4,000	$ 100	$ 2,100	$ 100
Troubled debt restructuring outstanding amount	12,400		12,400		$ 12,400		$ 13,300
Average impaired loans	35,100	38,100	35,500	34,500
Interest income recorded on impaired loans	700	500	1,500	1,400
Interest income related to impaired loans with impairment measured on present value of expected future cash flows	$ 40	$ 36	$ 102,000	$ 157,000