Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Goodwill [Roll Forward]
Balance, beginning of period	$ 232,932,000
Goodwill acquired during the period	98,297,000
Foreign currency translation	5,091,000
Balance, end of period	336,320,000		232,932,000
Intangible Assets [Abstract]
Gross carrying amount	121,690,000		79,076,000
Accumulated amortization	6,794,000		5,663,000
Net carrying amount	114,896,000		73,413,000
Weighted average amortization period (in years)	8.0		7.4
Amortization expense of intangible assets	3,100,000	500,000
Future amortization expense of intangible assets [Abstract]
For the remainder of the year ended 12/31/12	11,800,000
For the year ended 12/31/13	15,288,000
For the year ended 12/31/14	14,640,000
For the year ended 12/31/15	14,603,000
For the year ended 12/31/16	14,510,000
For the year ended 12/31/17	14,155,000
Thereafter	29,949,000
Oil Field [Member]
Goodwill [Roll Forward]
Balance, beginning of period	225,770,000
Goodwill acquired during the period	98,297,000
Foreign currency translation	5,024,000
Balance, end of period	329,091,000
Power Transmission [Member]
Goodwill [Roll Forward]
Balance, beginning of period	7,162,000
Foreign currency translation	67,000
Balance, end of period	7,229,000
Non Compete Agreements And Trademarks [Member]
Intangible Assets [Abstract]
Gross carrying amount	10,222,000		6,258,000
Accumulated amortization	1,211,000		1,091,000
Net carrying amount	9,011,000		5,167,000
Weighted average amortization period (in years)	6.5		5.1
Customer relationships and contracts [Member]
Intangible Assets [Abstract]
Gross carrying amount	111,468,000		72,818,000
Accumulated amortization	5,583,000		4,572,000
Net carrying amount	$ 105,885,000		$ 68,246,000
Weighted average amortization period (in years)	9.5		9.6