Segment and Geographic Information (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales		$ 223,322	$ 214,623	$ 223,357	$ 215,435	$ 172,647	$ 173,132	$ 182,674	$ 180,453	$ 876,737	$ 708,906	$ 746,652
Income from operations										80,987	47,546	64,214
Restructuring										(4,143)	(9,849)	(7,214)
Loss on partial settlement of pension plan										(1,720)
Net interest expense										7,710	11,679	12,164
Loss on extinguishment of convertible debt										1,797	1,989
Other non-operating expense (income), net										353	(7)	963
Total other non-operating (income) expense, net										9,860	13,661	13,127
Income before income taxes										71,127	33,885	51,087
Provision for income taxes										19,700	8,745	15,744
Net income										51,427	25,140	35,343
Total depreciation and amortization										36,025	29,898	30,121
Total assets		920,657				869,824				920,657	869,824
Property, Plant and Equipment		191,918				177,043				191,918	177,043
North America (primarily U.S.) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales										441,208	418,536	452,172
Property, Plant and Equipment		84,337				81,675				84,337	81,675
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales										342,867	217,736	218,857
Property, Plant and Equipment		100,733				89,672				100,733	89,672
Asia And Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales										92,662	72,634	75,623
Property, Plant and Equipment		6,847				5,696				6,847	5,696
Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Restructuring										(4,143)	(9,849)	(7,214)
Loss on partial settlement of pension plan										(1,720)
Operating Segments [Member] | Couplings, Clutches and Brakes [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales										441,887	305,406	342,299
Income from operations										47,215	20,941	38,750
Total depreciation and amortization										20,905	15,180	15,897
Total assets		547,738				511,934				547,738	511,934
Operating Segments [Member] | Electromagnetic Clutches and Brakes [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales										251,505	217,856	219,676
Income from operations										27,774	26,406	21,634
Total depreciation and amortization										4,950	4,615	4,565
Total assets		183,197				169,507				183,197	169,507
Operating Segments [Member] | Gearing [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales										191,789	192,003	192,252
Income from operations										22,238	22,718	21,094
Total depreciation and amortization										6,866	7,000	6,617
Total assets		155,541				147,829				155,541	147,829
Intersegment Eliminations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales										(8,444)	(6,359)	(7,575)
Corporate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Income from operations	[1]									(10,377)	(12,670)	(10,050)
Total depreciation and amortization										3,304	3,103	$ 3,042
Total assets	[2]	$ 34,181				$ 40,554				$ 34,181	$ 40,554

[1] Certain expenses are maintained at the corporate level and not allocated to the segments. These include various administrative expenses related to the corporate headquarters, depreciation on capitalized software costs, non-capitalizable software implementation costs, acquisition related expenses and impairment of intangibles.

[2] Corporate assets are primarily cash and cash equivalents, tax related asset accounts, certain capitalized software costs, property, plant and equipment and deferred financing costs.