Employee Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Summary of net periodic benefit cost
Interest cost	$ 948	$ 883	$ 1,896	$ 1,766
Expected return on plan assets	(1,043)	(1,077)	(2,086)	(2,154)
Amortization of net loss	463	513	926	1,026
Other	225	213	450	426
Net periodic benefit cost	593	$ 532	1,186	1,064
Company contribution			2,000	$ 1,400
Expected contributions remainder of current fiscal year	$ 2,600		$ 2,600