Nonpension Postretirement Benefits (Change in Accumulated Benefit Obligation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Nonpension Postretirement Benefit Plans
Change in projected benefit obligation:
Benefit obligation, beginning of year	$ 60,185	$ 68,101
Service Cost	798	856	$ 1,008
Interest cost	2,659	2,589	2,948
Plan participants' contributions	528	610
Actuarial (gain) loss	44	(8,027)
Exchange rate fluctuations	46	(346)
Benefits paid	(3,995)	(3,598)
Benefit obligation, end of year	60,265	60,185	68,101
Funded status and accrued benefit cost	(60,265)	(60,185)
U.S. Plans
Change in projected benefit obligation:
Benefit obligation, beginning of year	58,795	65,565
Service Cost	797	855	1,007
Interest cost	2,608	2,537	2,840
Plan participants' contributions	528	610
Actuarial (gain) loss	146	(7,287)
Exchange rate fluctuations	0	0
Benefits paid	(3,953)	(3,485)
Benefit obligation, end of year	58,921	58,795	65,565
Funded status and accrued benefit cost	(58,921)	(58,795)
Non-U.S. Plans
Change in projected benefit obligation:
Benefit obligation, beginning of year	1,390	2,536
Service Cost	1	1	1
Interest cost	51	52	108
Plan participants' contributions	0	0
Actuarial (gain) loss	(102)	(740)
Exchange rate fluctuations	46	(346)
Benefits paid	(42)	(113)
Benefit obligation, end of year	1,344	1,390	$ 2,536
Funded status and accrued benefit cost	$ (1,344)	$ (1,390)