BUSINESS ACQUISITIONS (Details) (USD $)	3 Months Ended		6 Months Ended							0 Months Ended					0 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Minimum [Member]	Jun. 30, 2013 Maximum [Member]	Jan. 31, 2012 Mid Continent Safety [Member]	Feb. 29, 2012 Pump & Power Equipment, Inc. [Member]	Apr. 02, 2012 Aledco, Inc. [Member]	May 01, 2012 Industrial Paramedic Services [Member] location	May 01, 2012 Industrial Paramedic Services [Member] Promissory note [Member]	Jul. 11, 2012 HSE Integrated Ltd. [Member]	May 31, 2012 Austin and Denholm Industrial Sales Alberta, Inc. [Member]	Oct. 01, 2012 Jerzy Supply, Inc. [Member]	Apr. 16, 2013 National Process Equipment Inc. [Member]	Jun. 30, 2013 National Process Equipment Inc. [Member]	May 17, 2013 Tucker Tool Company, Inc. [Member]
Purchase price allocation [Abstract]
Cash	$ 12,374,000		$ 12,374,000
Accounts Receivable, net	50,385,000		50,385,000
Inventory	10,985,000		10,985,000
Property and equipment	38,230,000		38,230,000
Goodwill and intangibles	120,817,000		120,817,000
Other assets	3,402,000		3,402,000
Assets acquired	236,193,000		236,193,000
Current liabilities assumed	(47,243,000)		(47,243,000)
Non current liabilities assumed	(20,987,000)		(20,987,000)
Net assets acquired	167,963,000		167,963,000
Business Acquisition [Line Items]
Purchase price							3,700,000	1,900,000	8,100,000	25,300,000		85,000,000	2,700,000	5,300,000	40,100,000		5,000,000
Borrowings under existing credit facility										20,600,000					36,600,000
Goodwill on acquisition							1,200,000	700,000	3,400,000	12,100,000		27,600,000	300,000	0	25,800,000		3,600,000
Number of shares issued on acquisition (in shares)										19,685					52,542
Number of operating locations										3
Borrowings under notes											2,500,000
Stated interest rate (in hundredths)											5.00%
Share price (in dollars per share)												$ 1.80
Liabilities assumed on acquisition												4,000,000
Transaction cost												3,000,000
Earnout amount															6,000,000
Fair value of earnout recorded at acquisition date															2,900,000
Earnout liability																2,900,000
Discount rate for valuation of acquired intangibles (in hundredths)					15.90%	18.00%
Sales from business acquisitions	55,300,000		98,700,000
Earnings from business acquisitions	400,000		2,500,000
Pro Forma Information [Abstract]
Net sales	312,326,000	313,222,000	625,464,000	625,734,000
Net income	$ 13,834,000	$ 12,902,000	$ 27,781,000	$ 26,275,000
Per share data [Abstract]
Basic earnings (in dollars per share)	$ 0.96	$ 0.89	$ 1.92	$ 1.82
Diluted earnings (in dollars per share)	$ 0.91	$ 0.85	$ 1.82	$ 1.73