BUSINESS ACQUISITIONS (Details)	3 Months Ended		9 Months Ended					0 Months Ended			0 Months Ended
	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Jul. 11, 2012 USD ($)	Dec. 31, 2011 USD ($)	Oct. 10, 2011 Kenneth Crosby [Member] USD ($)	Dec. 30, 2011 C.W.Rod Tool Company [Member] USD ($)	Jan. 31, 2012 Mid-Continent Safety [Member] USD ($)	Feb. 29, 2012 Pump & Power Equipment, Inc. [Member] USD ($)	May 01, 2012 Industrial Paramedic Services [Member] USD ($)	May 01, 2012 Industrial Paramedic Services [Member] Promissory Notes [Member] USD ($)	Apr. 02, 2012 Aledco, Inc. [Member] USD ($)	Jul. 11, 2012 HSE Integrated Ltd. [Member] USD ($)	Jul. 11, 2012 HSE Integrated Ltd. [Member] CAD
Business Acquisition [Line Items]
Purchase price							$ 15,600,000	$ 41,700,000	$ 3,800,000	$ 1,900,000	$ 24,100,000		$ 8,000,000	$ 85,000,000
Borrowings under existing credit facility							15,600,000	41,700,000	3,800,000	1,900,000	20,600,000		8,000,000
Goodwill on acquisition							5,800,000	10,000,000	1,200,000	700,000	11,900,000		2,900,000	22,600,000
Purchase price, common stock								1,100,000
Number of shares issued on acquisition (in shares)								35,714			19,685
Purchase price, cash paid								41,700,000
Cash paid in form of checks in connection with a business acquisition						36,700,000		36,700,000
Number of locations in which entity operates											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 acquisiton														4,000,000
Transaction costs														3,000,000
New credit facility, maximum borrowing capacity					325,000,000
Sales contributed by acquisitions that occurred subsequent to September 30, 2011	66,700,000		137,600,000
Income before income taxes contributed by acquisitions that occurred subsequent to September 30, 2011	3,400,000		7,400,000
Purchase price allocation [Abstract]
Cash	11,976,000		11,976,000
Accounts Receivable, net	49,448,000		49,448,000
Inventory, net	16,033,000		16,033,000
Property and equipment	29,139,000		29,139,000
Goodwill and intangibles	114,814,000		114,814,000
Other assets	2,839,000		2,839,000
Assets acquired	224,249,000		224,249,000
Current liabilities assumed	(34,374,000)		(34,374,000)
Non-current liabilities assumed	(13,753,000)		(13,753,000)
Net assets acquired	176,122,000		176,122,000
Pro Forma Information [Abstract]
Net sales	293,110,000	273,167,000	877,091,000	781,537,000
Net income	$ 13,137,000	$ 11,696,000	$ 39,233,000	$ 28,751,000
Per share data [Abstract]
Basic earnings (in dollars per share)	$ 0.91	$ 0.81	$ 2.72	$ 2.00
Diluted earnings (in dollars per share)	$ 0.86	$ 0.77	$ 2.58	$ 1.89