Pension Plan (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Retirement Benefits [Abstract]
Service cost	$ 253	$ 169	$ 759	$ 506
Interest cost on projected benefit obligation	782	701	2,346	2,104
Expected return on plan assets	(1,181)	(1,354)	(3,543)	(4,063)
Net amortization and deferral	720	672	2,160	2,017
Net periodic pension cost	574	$ 188	1,722	$ 564
Defined Benefit Plan, Non-service cost	$ 300		$ 1,000