Acquisitions (Details) (USD $)	12 Months Ended		12 Months Ended				12 Months Ended
	Dec. 31, 2012	Sep. 01, 2011 Pentagon Optimization Services, Inc [Member]	Dec. 31, 2011 Quinns Oilfield Supply Ltd [Member]	Dec. 31, 2010 Quinns Oilfield Supply Ltd [Member]	Dec. 31, 2012 Quinns Oilfield Supply Ltd [Member]	Dec. 01, 2011 Quinns Oilfield Supply Ltd [Member]	Dec. 31, 2012 Datac Instrumentation Limited [Member]	Jan. 19, 2012 Datac Instrumentation Limited [Member]	Feb. 29, 2012 Zenith Oilfield Technology Ltd [Member]
Acquisitions [Line Items]
Business acquisition, date of purchase		Sep. 01, 2011				Dec. 01, 2011		Jan. 19, 2012	Feb. 29, 2012
Cash paid at closing, net		$ 18,982,000				$ 311,003,000		$ 18,584,000	$ 133,972,000
Cash paid as working capital true-up						250,000
Royalty consideration		2,381,000
Common stock paid at closing								8,416,000
Total consideration paid		21,363,000				311,253,000		27,000,000	133,972,000
Restricted shares issued in business acquisition (in shares)							116,716
Business acquisition equity interests issued fair value per share (in dollars per share)								$ 72.09
Purchase price		21,363,000				311,253,000		27,000,000	133,972,000
Receivables		1,763,000				27,680,000		323,000	13,236,000
Inventories		1,183,000				23,006,000		449,000	4,226,000
Other current assets		470,000				715,000		57,000	7,711,000
Property, plant and equipment		680,000				62,734,000		51,000	518,000
Intangible assets		4,195,000				57,400,000
Non-compete agreements and trademarks								350,000	3,614,000
Customer relationship and contracts								5,983,000	32,665,000
Other long term assets									355,000
Indemnification asset								5,500,000
Accounts payable		(258,000)				(24,924,000)		(178,000)	(3,698,000)
Other accrued liabilities		(981,000)				(9,046,000)		(484,000)	(2,144,000)
Uncertain tax liability								(5,500,000)
Deferred tax liabilities						(41)		(229,000)	(9,380,000)
Goodwill recorded		14,311,000				173,729,000		20,678,000	86,869,000
Escrow account balance							5,500,000
Business acquisition cost of acquired entity additional consideration					250,000
Number of businesses whose assets acquired	2
Pro forma information as if quinn acquisition occurred at beginning of year [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