Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Goodwill [Roll Forward]
Balance, beginning of period			$ 232,932,000
Goodwill acquired during the period			98,468,000
Foreign currency translation			(470,000)
Balance, end of period	330,930,000		330,930,000		232,932,000
Intangible Assets [Abstract]
Gross Carrying Amount	121,653,000		121,653,000		79,076,000
Accumulated Amortization	12,749,000		12,749,000		5,663,000
Net	108,904,000		108,904,000		73,413,000
Weighted Average Amortization Period (in years)			8.0		7.4
Amortization expense of intangible assets	4,000,000	500,000	7,100,000	1,000,000
Future amortization expense of intangible assets [Abstract]
For the remainder of the year ended 12/31/12			7,600,000
For the year ended 12/31/13			15,022,000
For the year ended 12/31/14			14,383,000
For the year ended 12/31/15			14,346,000
For the year ended 12/31/16			14,255,000
For the year ended 12/31/17			13,962,000
Thereafter			29,319,000
Non-compete agreements and trademarks [Member]
Intangible Assets [Abstract]
Gross Carrying Amount	10,201,000		10,201,000		6,258,000
Accumulated Amortization	1,653,000		1,653,000		1,091,000
Net	8,548,000		8,548,000		5,167,000
Weighted Average Amortization Period (in years)			6.5		5.1
Customer relationships and contracts [Member]
Intangible Assets [Abstract]
Gross Carrying Amount	111,452,000		111,452,000		72,818,000
Accumulated Amortization	11,096,000		11,096,000		4,572,000
Net	100,356,000		100,356,000		68,246,000
Weighted Average Amortization Period (in years)			9.5		9.6
Oil Field [Member]
Goodwill [Roll Forward]
Balance, beginning of period			225,770,000
Goodwill acquired during the period			98,468,000
Foreign currency translation			(418,000)
Balance, end of period	323,820,000		323,820,000
Power Transmission [Member]
Goodwill [Roll Forward]
Balance, beginning of period			7,162,000
Foreign currency translation			(52,000)
Balance, end of period	$ 7,110,000		$ 7,110,000