Loans Receivable and Allowance for Loan Losses, Loans modified as TDRs (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) loan contract	Sep. 30, 2018 loan contract	Sep. 30, 2019 USD ($) loan contract	Sep. 30, 2018 loan contract	Dec. 31, 2018 USD ($) contract
Loans modified [Abstract]
Number of modifications | loan	0	0	0	0
TDRs loans accounted under method [Abstract]
Number of modifications	38		38		42
Accrual status | $	$ 9,023		$ 9,023		$ 10,698
Number of modifications	2		2		3
Nonaccrual status | $	$ 292		$ 292		$ 446
Total number of modifications	40		40		45
Total balance of modifications | $	$ 9,315		$ 9,315		$ 11,144
Number of contract, subsequent defaults	0	0	0	0
Residential Mortgage [Member]
TDRs loans accounted under method [Abstract]
Number of modifications	32		32		36
Accrual status | $	$ 7,828		$ 7,828		$ 9,469
Number of modifications	2		2		3
Nonaccrual status | $	$ 292		$ 292		$ 446
Total number of modifications	34		34		39
Total balance of modifications | $	$ 8,120		$ 8,120		$ 9,915
Commercial Real Estate [Member]
TDRs loans accounted under method [Abstract]
Number of modifications	2		2		2
Accrual status | $	$ 993		$ 993		$ 1,019
Total number of modifications	2		2		2
Total balance of modifications | $	$ 993		$ 993		$ 1,019
ADC [Member]
TDRs loans accounted under method [Abstract]
Number of modifications	1		1		1
Accrual status | $	$ 131		$ 131		$ 134
Total number of modifications	1		1		1
Total balance of modifications | $	$ 131		$ 131		$ 134
Consumer [Member]
TDRs loans accounted under method [Abstract]
Number of modifications	3		3		3
Accrual status | $	$ 71		$ 71		$ 76
Total number of modifications	3		3		3
Total balance of modifications | $	$ 71		$ 71		$ 76