Quarterly Financial Data (Schedule of Revised Amounts for Certain Income Statement Accounts) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net sales	$ 251,600	$ 251,900	$ 255,400	$ 223,600	$ 226,700	$ 222,100	$ 215,600	$ 199,300	$ 213,000	$ 191,300	$ 203,200	$ 172,300		$ 982,479	$ 863,717	$ 779,839
Gross profit	87,900	92,400	91,700	77,700	77,500	79,600	63,200	76,000	77,500	72,600	78,500	72,700		349,749	296,283	301,284
Operating income	37,400	40,800	42,200	17,000										137,408	78,676	94,132
Net income/(loss) attributable to the Company	$ 17,600	$ 27,700	$ 29,900	$ 7,700	$ 5,900	$ 15,300	$ 1,100	$ 10,800	$ 15,700	$ 13,100	$ 10,400	$ 13,500		$ 82,891	$ 33,111	$ 52,733
Basic earnings per share	$ 0.54	$ 0.86	$ 0.93	$ 0.24	$ 0.19	$ 0.47	$ 0.03	$ 0.34	$ 0.49	$ 0.41	$ 0.32	$ 0.42		$ 2.57	$ 1.03	$ 1.64
Diluted earnings per share	$ 0.54	$ 0.86	$ 0.93	$ 0.24	$ 0.19	$ 0.47	$ 0.03	$ 0.34	$ 0.49	$ 0.41	$ 0.32	$ 0.42		$ 2.57	$ 1.03	$ 1.64
As previously Reported [Member]
Net income/(loss) attributable to the Company		$ 28,200	$ 30,400	$ 10,200									$ 68,800
Basic earnings per share		$ 0.87	$ 0.94	$ 0.32									$ 2.13
Diluted earnings per share		$ 0.87	$ 0.94	$ 0.32									$ 2.13
Increase/ (decrease) [Member]
Net income/(loss) attributable to the Company		$ (500)	$ (500)	$ (2,500)									$ 65,300
Basic earnings per share		$ (0.01)	$ (0.01)	$ (0.08)									$ 2.02
Diluted earnings per share		$ (0.01)	$ (0.01)	$ (0.08)									$ 2.02
As Revised [Member]
Net income/(loss) attributable to the Company		$ 27,700	$ 29,900	$ 7,700									$ 65,300
Basic earnings per share		$ 0.86	$ 0.93	$ 0.24									$ 2.02
Diluted earnings per share		$ 0.86	$ 0.93	$ 0.24									$ 2.02
Machine Clothing [Member]
Net sales	$ 150,700	$ 157,600	$ 161,800	$ 141,800										$ 611,900
Gross profit	73,300	78,700	79,100	66,300										297,400
Operating income	$ 42,900	49,700	50,300	26,900										$ 169,800
Machine Clothing [Member] | As previously Reported [Member]
Net sales		159,000	162,600	148,200									$ 469,800
Gross profit		79,400	79,600	70,200									229,200
Operating income		50,800	50,800	30,800									131,900
Machine Clothing [Member] | Increase/ (decrease) [Member]
Net sales		(1,400)	(800)	(6,400)									(8,600)
Gross profit		(700)	(500)	(3,900)									(5,100)
Operating income		(600)	(500)	(3,900)									(5,000)
Machine Clothing [Member] | As Revised [Member]
Net sales		157,600	161,800	141,800									461,200
Gross profit		78,700	79,100	66,300									224,100
Operating income		$ 49,700	$ 50,300	$ 26,900									$ 126,900