Special Charges (Restructuring Programs Summary) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Accrued restructuring charges	$ 663	$ 1,645	$ 3,063
Total restructuring charges, net	8,975	4,634	5,246
Charges paid / settled, net	(8,020)	(5,616)	(6,664)
Accrued restructuring charges	1,618	663	1,645
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Facility related expenses (recoveries)	4,493	(119)	699
Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Total restructuring charges, net	4,482	4,753	4,547
Energy [Member]
Restructuring Reserve [Roll Forward]
Total restructuring charges, net	3,185	2,903	1,963
Energy [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Facility related expenses (recoveries)	792	(376)	447
Energy [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Total restructuring charges, net	2,393	3,279	1,516
Advanced Flow Solutions [Member]
Restructuring Reserve [Roll Forward]
Total restructuring charges, net	5,790	1,731	2,966
Advanced Flow Solutions [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Facility related expenses (recoveries)	3,701	257	252
Advanced Flow Solutions [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Total restructuring charges, net	2,089	1,474	2,714
Corporate [Member]
Restructuring Reserve [Roll Forward]
Total restructuring charges, net	0	0	317
Corporate [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Facility related expenses (recoveries)	0	0	0
Corporate [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Total restructuring charges, net	$ 0	$ 0	$ 317