BUSINESS ACQUISITIONS (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended			0 Months Ended	3 Months Ended		0 Months Ended			0 Months Ended		0 Months Ended		0 Months Ended		0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Business acquired in 2013 [Member]	Sep. 30, 2014 Business acquired in 2013 [Member]	Sep. 30, 2014 Business acquired in 2014 [Member]	Sep. 30, 2014 Business acquired in 2014 [Member]	Sep. 30, 2014 Minimum [Member]	Sep. 30, 2014 Maximum [Member]	Apr. 16, 2013 National Process Equipment Inc. [Member]	Dec. 31, 2013 National Process Equipment Inc. [Member]	Sep. 30, 2014 National Process Equipment Inc. [Member]	May 17, 2014 Tucker Tool Company, Inc. [Member]	Sep. 30, 2014 Tucker Tool Company, Inc. [Member]	May 17, 2013 Tucker Tool Company, Inc. [Member]	Jul. 02, 2013 Alaska Pump and Supply, Inc. [Member]	Sep. 30, 2014 Alaska Pump and Supply, Inc. [Member]	Jul. 31, 2013 Tool Tech Industrial Machine and Supply, Inc. [Member]	Sep. 30, 2014 Tool Tech Industrial Machine and Supply, Inc. [Member]	Jan. 02, 2014 B27, LLC [Member]	Sep. 30, 2014 B27, LLC [Member]	May 01, 2014 Machinery Tooling and Supply LLC [Member]	Sep. 30, 2014 Machinery Tooling and Supply LLC [Member]	May 01, 2014 Machinery Tooling and Supply LLC [Member]
Purchase price allocation [Abstract]
Cash	$ 3,774,000		$ 3,774,000											$ 0		$ 0			$ 0		$ 430,000		$ 2,538,000		$ 806,000
Accounts Receivable, net	75,087,000		75,087,000											14,549,000		505,000			1,424,000		1,505,000		51,448,000		5,656,000
Inventory	17,827,000		17,827,000											6,883,000		209,000			1,332,000		409,000		6,472,000		2,522,000
Property and equipment	18,638,000		18,638,000											3,317,000		0			172,000		19,000		14,573,000		557,000
Goodwill and intangibles	334,173,000		334,173,000											39,345,000		4,678,000			12,241,000		7,254,000		262,250,000		8,405,000
Other assets	2,311,000		2,311,000											698,000		0			389,000		2,000		1,163,000		59,000
Assets acquired	451,810,000		451,810,000											64,792,000		5,392,000			15,558,000		9,619,000		338,444,000		18,005,000
Current liabilities assumed	52,658,000		52,658,000											19,175,000		391,000			1,079,000		1,987,000		26,690,000		3,336,000
Non-current liabilities assumed	25,270,000		25,270,000											5,649,000		0			1,419,000		0		18,202,000		0
Net assets acquired	373,882,000		373,882,000											39,968,000		5,001,000			13,060,000		7,632,000		293,552,000		14,669,000
Maximum period of information after acquisition date for revision in estimates									1 year
Purchase price												40,000,000			5,000,000			13,000,000		7,600,000		293,600,000		14,900,000
Borrowings under existing credit facility												36,600,000
Number of shares issued on acquisition (in shares)												52,542										36,000
Earn-out amount												6,000,000
Fair value of earn-out recorded at acquisition date												2,800,000
Earn-out liability													0
Reduction in selling, general and administrative expense													2,800,000
Goodwill acquired	373,719,000		373,719,000		188,110,000							24,600,000					3,200,000	8,100,000		4,900,000		181,100,000				4,300,000
Intangible assets acquired												14,800,000					1,500,000	4,100,000		2,400,000		81,100,000				4,100,000
Purchase price financed under common stock issued																						4,000,000
Transaction cost																						1,000,000
Nontax deductible goodwill or intangible assets																						209,800,000
Discount rate for valuation of acquired intangibles (in hundredths)										13.50%	15.90%
Sales from business acquisitions						25,200,000	75,300,000	45,300,000	125,400,000
Earnings (loss) before taxes from business acquisitions						600,000	200,000	3,400,000	4,300,000
Pro Forma Information [Abstract]
Net sales	387,053,000	391,515,000	1,130,108,000	1,122,403,000
Net income	$ 17,643,000	$ 20,988,000	$ 45,103,000	$ 50,947,000
Per share data [Abstract]
Basic earnings (in dollars per share)	$ 1.20	$ 1.45	$ 3.07	$ 3.51
Diluted earnings (in dollars per share)	$ 1.14	$ 1.37	$ 2.90	$ 3.32