Pension Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Retirement Benefits [Abstract]
Net service cost	$ (1,107)	$ (1,355)	$ (2,216)	$ (1,625)
Interest cost	(166)	(405)	(332)	(486)
Expected return on plan assets	109	252	217	302
Administrative charges	(72)	(108)	(143)	(130)
Net periodic pension cost	$ (1,236)	$ (1,616)	$ (2,474)	$ (1,939)