Employee Pension Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Summary of net periodic benefit cost
Interest cost	$ 975	$ 1,053
Expected return on plan assets	(1,088)	(1,203)
Amortization (adjustment) of net loss	456	427
Other	213	150
Net periodic benefit cost	556	427
Company contribution	800	$ 300
Expected contributions remainder of current fiscal year	$ 1,800