Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Business Segment Information [Abstract]
Number of operating business segments	2								2
Sales by segment [Abstract]
Total sales	$ 279,300	$ 231,700	$ 226,800	$ 194,400	$ 193,500	$ 172,100	$ 152,900	$ 127,100	$ 932,135		$ 645,643		$ 521,359
Gross sales									950,523		650,887		527,242
Inter-segment sales									(18,388)		(5,244)		(5,883)
Net sales	279,300	231,700	226,800	194,400	193,500	172,100	152,900	127,100	932,135		645,643		521,359
Earnings (loss) before income taxes [Abstract]
Total earnings (loss) before income taxes									105,469		67,445		33,012
Operating income (loss)									107,478		67,659		31,424
Other (expense) income, net									(2,009)		(214)		1,588
Earnings from continuing operations before income tax provision									105,469		67,445		33,012
Assets by segment [Abstract]
Segment Total assets	1,096,705				621,078				1,096,705		621,078		541,590
Capital expenditures by segment [Abstract]
Total capital expenditures									103,559		60,363		39,825
Depreciation/amortization by segment [Abstract]
Total depreciation/amortization									24,266		21,158		18,457
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales	279,300	231,700	226,800	194,400	193,500	172,100	152,900	127,100	932,135		645,643		521,359
Total P, P & E, net	346,430				203,717				346,430		203,717		159,770
United States [Member]
Sales by segment [Abstract]
Total sales									582,947		390,129		290,924
Net sales									582,947		390,129		290,924
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									582,947		390,129		290,924
Total P, P & E, net	175,921				145,842				175,921		145,842		121,419
Europe [Member]
Sales by segment [Abstract]
Total sales									64,926		46,799		50,362
Net sales									64,926		46,799		50,362
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									64,926		46,799		50,362
Total P, P & E, net	86,213				33,051				86,213		33,051		14,827
Canada [Member]
Sales by segment [Abstract]
Total sales									88,317		33,668		19,039
Net sales									88,317		33,668		19,039
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									88,317		33,668		19,039
Total P, P & E, net	69,047				8,655				69,047		8,655		9,072
Latin America [Member]
Sales by segment [Abstract]
Total sales									100,287		103,390		94,972
Net sales									100,287		103,390		94,972
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									100,287		103,390		94,972
Total P, P & E, net	14,884				15,924				14,884		15,924		14,211
Middle East/North Africa [Member]
Sales by segment [Abstract]
Total sales									69,703		43,913		40,310
Net sales									69,703		43,913		40,310
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									69,703		43,913		40,310
Other [Member]
Sales by segment [Abstract]
Total sales									25,955		27,744		25,752
Net sales									25,955		27,744		25,752
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									25,955		27,744		25,752
Total P, P & E, net	365				245				365		245		241
Continuing Operations [Member]
Assets by segment [Abstract]
Segment Total assets	1,096,705				620,442				1,096,705		620,442		540,779
Discontinued Operations [Member]
Assets by segment [Abstract]
Segment Total assets	0				636				0		636		811
Oil Field [Member]
Sales by segment [Abstract]
Total sales									736,488		477,867		349,168
Gross sales									743,545		479,732		351,766
Inter-segment sales									(7,057)		(1,865)		(2,598)
Net sales									736,488		477,867		349,168
Earnings (loss) before income taxes [Abstract]
Total earnings (loss) before income taxes									91,278		57,690		21,405
Operating income (loss)									93,058		57,749		20,458
Other (expense) income, net									(1,780)		(59)		947
Earnings from continuing operations before income tax provision									91,278		57,690		21,405
Assets by segment [Abstract]
Segment Total assets	869,519				376,324				869,519		376,324		293,140
Capital expenditures by segment [Abstract]
Total capital expenditures									83,871		43,938		27,384
Depreciation/amortization by segment [Abstract]
Total depreciation/amortization									16,548		13,484		11,561
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									736,488		477,867		349,168
Power Transmission [Member]
Sales by segment [Abstract]
Total sales									195,647		167,776		172,191
Gross sales									206,978		171,155		175,476
Inter-segment sales									(11,331)		(3,379)		(3,285)
Net sales									195,647		167,776		172,191
Earnings (loss) before income taxes [Abstract]
Total earnings (loss) before income taxes									16,402		10,937		17,040
Operating income (loss)									16,298		10,911		16,966
Other (expense) income, net									104		26		74
Earnings from continuing operations before income tax provision									16,402		10,937		17,040
Assets by segment [Abstract]
Segment Total assets	153,429				134,004				153,429		134,004		128,789
Capital expenditures by segment [Abstract]
Total capital expenditures									5,995		8,445		12,168
Depreciation/amortization by segment [Abstract]
Total depreciation/amortization									6,893		6,752		5,951
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									195,647		167,776		172,191
Corporate & Other [Member]
Sales by segment [Abstract]
Total sales									0	[1]	0	[1]	0	[1]
Gross sales									0	[1]	0	[1]	0	[1]
Inter-segment sales									0	[1]	0	[1]	0	[1]
Net sales									0	[1]	0	[1]	0	[1]
Earnings (loss) before income taxes [Abstract]
Total earnings (loss) before income taxes									(2,211)	[1]	(1,182)	[1]	(5,433)	[1]
Operating income (loss)									(1,878)	[1]	(1,001)	[1]	(6,000)	[1]
Other (expense) income, net									(333)	[1]	(181)	[1]	567	[1]
Earnings from continuing operations before income tax provision									(2,211)	[1]	(1,182)	[1]	(5,433)	[1]
Assets by segment [Abstract]
Segment Total assets	73,757				110,114				73,757		110,114		118,850
Capital expenditures by segment [Abstract]
Total capital expenditures									13,693		7,980		273
Depreciation/amortization by segment [Abstract]
Total depreciation/amortization									825		922		945
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales									$ 0	[1]	$ 0	[1]	$ 0	[1]

[1] Corporate & Other includes the litigation reserve.