Goodwill and Intangible Assets - Changes in Goodwill (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Goodwill [Roll Forward]
Net goodwill, beginning balance	$ 188,841
Measurement period adjustment related to acquisition of Stromag	2,205
Impact of changes in foreign currency and other	1,815
Net goodwill, ending balance	192,861
Couplings, Clutches and Brakes [Member]
Goodwill [Roll Forward]
Net goodwill, beginning balance	104,465
Measurement period adjustment related to acquisition of Stromag	1,865
Impact of changes in foreign currency and other	1,596
Net goodwill, ending balance	107,926
Electromagnetic Clutches and Brakes [Member]
Goodwill [Roll Forward]
Net goodwill, beginning balance	37,161
Measurement period adjustment related to acquisition of Stromag	340
Impact of changes in foreign currency and other	114
Net goodwill, ending balance	37,615
Gearing [Member]
Goodwill [Roll Forward]
Net goodwill, beginning balance	47,215
Impact of changes in foreign currency and other	105
Net goodwill, ending balance	$ 47,320