Goodwill and Intangible Assets - Changes in Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Net goodwill, beginning balance	$ 97,309	$ 102,087
Acquisition of Stromag	93,125
Impact of changes in foreign currency and other	(1,593)	(4,778)
Net goodwill, ending balance	188,841	97,309
Operating Segments [Member] | Couplings, Clutches and Brakes [Member]
Goodwill [Roll Forward]
Net goodwill, beginning balance	25,290	28,464
Acquisition of Stromag	80,340
Impact of changes in foreign currency and other	(1,165)	(3,174)
Net goodwill, ending balance	104,465	25,290
Operating Segments [Member] | Electromagnetic Clutches and Brakes [Member]
Goodwill [Roll Forward]
Net goodwill, beginning balance	24,661	25,142
Acquisition of Stromag	12,785
Impact of changes in foreign currency and other	(285)	(481)
Net goodwill, ending balance	37,161	24,661
Operating Segments [Member] | Gearing [Member]
Goodwill [Roll Forward]
Net goodwill, beginning balance	47,358	48,481
Impact of changes in foreign currency and other	(143)	(1,123)
Net goodwill, ending balance	$ 47,215	$ 47,358