Employee Benefit Plans, Noncontributory Defined Benefit Pension Plan (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) Plan	Sep. 30, 2016 USD ($)
Employee Benefit Plans [Abstract]
Number of plans | Plan			2
Pension Plan [Member]
Components of net periodic benefit cost [Abstract]
Service cost	$ 87	$ 90	$ 262	$ 269
Interest cost	168	172	503	517
Expected return on plan assets	(274)	(260)	(821)	(780)
Net amortization and deferral	56	61	168	182
Net periodic benefit cost	$ 37	$ 63	112	$ 188
Employer contributions			$ 400