Employee Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Summary of net periodic benefit cost
Interest cost	$ 948	$ 883
Expected return on plan assets	(1,043)	(1,077)
Amortization of net loss	463	513
Other	225	213
Net periodic benefit cost	593	532
Company contribution	700	$ 800
Expected contributions remainder of current fiscal year	$ 3,900