Name:	us-gaap_FiniteLivedIntangibleAssetsAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The accumulated amount of amortization of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
Goodwill and Intangible Assets (Details) (USD $)	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Goodwill [Roll Forward]
Balance, beginning of period			$ 53,011,000
Goodwill acquired during the period			14,538,000
Foreign currency translation			(1,377,000)
Balance, end of period	66,172,000		66,172,000		53,011,000
Intangible Assets [Abstract]
Gross carrying amount	21,624,000		21,624,000		17,733,000
Accumulated amortization	4,547,000		4,547,000		2,994,000
Net carrying amount	17,077,000		17,077,000		14,739,000
Weighted average amortization period (in years)			8.4		7.0
Amortization expense of intangible assets	500,000	400,000	1,600,000	1,300,000
Future amortization expense of intangible assets [Abstract]
For the remainded of the year ended 12/31/11			500,000
For the year ended 12/31/12			2,263,000
For the year ended 12/31/13			2,236,000
For the year ended 12/31/14			2,085,000
For the year ended 12/31/15			2,048,000
For the year ended 12/31/16			1,977,000
Thereafter			6,021,000
Oil Field [Member]
Goodwill [Roll Forward]
Balance, beginning of period			45,862,000
Goodwill acquired during the period			14,538,000
Foreign currency translation			(1,380,000)
Balance, end of period	59,020,000		59,020,000
Power Transmission [Member]
Goodwill [Roll Forward]
Balance, beginning of period			7,149,000
Foreign currency translation			3,000
Balance, end of period	7,152,000		7,152,000
Non-compete agreements and trademarks [Member]
Intangible Assets [Abstract]
Gross carrying amount	2,945,000		2,945,000		2,550,000
Accumulated amortization	928,000		928,000		619,000
Net carrying amount	2,017,000		2,017,000		1,931,000
Weighted average amortization period (in years)			6.1		6.3
Customer relationships and contracts [Member]
Intangible Assets [Abstract]
Gross carrying amount	18,679,000		18,679,000		15,183,000
Accumulated amortization	3,619,000		3,619,000		2,375,000
Net carrying amount	$ 15,060,000		$ 15,060,000		$ 12,808,000
Weighted average amortization period (in years)			11.6		10.0