Employee Benefit Plans - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Benefits paid	$ 825
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Benefits paid		$ 100
Estimated other postretirement benefits to be paid in 2017			$ 400