Acquisitions (Details) (USD $)	3 Months Ended								12 Months Ended									1 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	Dec. 01, 2011 Pentagon Optimization Services, Inc [Member]	Oct. 01, 2011 Pentagon Optimization Services, Inc [Member]	Sep. 30, 2011 Pentagon Optimization Services, Inc [Member]	Sep. 01, 2011 Pentagon Optimization Services, Inc [Member]	Mar. 01, 2009 International Lift Systems [Member]	Nov. 01, 2010 Petro Hydraulic Lift Systems LLC [Member]	Dec. 31, 2011 Quinn's Oilfield Supply Ltd [Member]	Dec. 31, 2011 Quinn's Oilfield Supply Ltd [Member]	Dec. 31, 2010 Quinn's Oilfield Supply Ltd [Member]	Dec. 01, 2011 Quinn's Oilfield Supply Ltd [Member]
Business Acquisition [Line Items]
Business acquisition, date of purchase															Sep. 01, 2011	Mar. 01, 2009	Nov. 01, 2010				Dec. 01, 2011
Purchase price hold back, total																$ 4,500,000
Number of installment payments																3
Purchase price hold back, installment payment amount																1,500,000
Interest rate on hold back amount (in hundredths)																4.00%
Term of royalty agreement (in years)													10Y				10Y
Royalty rate, first half of term (in hundredths)																	5.00%
Royalty rate, second half of term (in hundredths)																	8.00%
Royalty rate													10.00%
Cash paid at closing, net												18,982,000									311,003,000
Royalty consideration												2,381,000
Total consideration paid												21,363,000		21,363,000		50,000,000	15,900,000				311,003,000
Purchase price												21,363,000		21,363,000		50,000,000	15,900,000				311,003,000
Receivables														1,763,000							28,989,000
Inventories														1,183,000							25,169,000
Other current assets														0							1,349,000
Property, plant and equipment														680,000							63,051,000
Intangible assets														4,195,000							57,400,000
Accounts payable														(258,000)							(24,345,000)
Other short-term accrued liabilities														2,316,000							(9,036,000)
Goodwill recorded														11,484,000		28,600,000	7,800,000				168,426,000
Supplemental Pro Forma Data [Abstract]
Sales																			1,070,623,000	761,327,000
Net earnings																			75,601,000	39,467,000
Diluted earnings per share from continuing operations (in dollars per share)																			$ 2.45	$ 1.36
Revenue	279,300,000	231,700,000	226,800,000	194,400,000	193,500,000	172,100,000	152,900,000	127,100,000	932,135,000	645,643,000	521,359,000							13,100,000
Net income	$ 20,700,000	$ 14,400,000	$ 18,500,000	$ 12,400,000	$ 14,300,000	$ 12,600,000	$ 10,600,000	$ 6,000,000	$ 65,971,000	$ 43,823,000	$ 22,026,000							$ 700,000