Acquisitions Acquisitions - Other Acquisitions (Details) (USD $)	3 Months Ended								12 Months Ended				9 Months Ended	12 Months Ended					2 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Oct. 16, 2014	Jun. 30, 2014	Mar. 31, 2013	Jun. 30, 2013	Sep. 30, 2013	Jun. 30, 2012	Feb. 23, 2012		Oct. 17, 2014
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired									$ 382,880,000	$ 105,790,000		$ 89,880,000
Net sales	350,570,000	380,120,000	403,000,000	365,390,000	320,190,000	354,910,000	377,750,000	335,750,000	1,499,080,000	1,388,600,000		1,267,510,000
Business Combination, Bargain Purchase, Gain Recognized, Amount									0	2,880,000		0
Allfast Fasteners [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred													366,950,000
Payments to Acquire Businesses, Net of Cash Acquired													351,220,000
Payments to Acquire Business Two, Net of Cash Acquired		27,500,000
Business Acquisition, Percentage of Voting Interests Acquired																					100.00%
Net sales														10,000,000
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred										118,160,000
Payments to Acquire Businesses, Net of Cash Acquired										105,790,000
Business Acquisition, Deferred Purchase Price and Contingent Consideration										12,370,000	[1]	14,400,000
Business Acquisition, Percentage of Voting Interests Acquired					100.00%					100.00%
Business Acquisition, Cost of Acquired Entity, Cash Paid												26,800,000
Business Acquisition, Martinic [Member]
Business Acquisition [Line Items]
Net sales												13,000,000
Business Acquisition, Wulfrun [Member]
Business Acquisition [Line Items]
Net sales												10,000,000
Business Acquisition, Witter [Domain]
Business Acquisition [Line Items]
Net sales															20,000,000
Business Acquisition, AL-KO [Domain]
Business Acquisition [Line Items]
Net sales																16,000,000
Business Combination, Bargain Purchase, Gain Recognized, Amount										2,900,000
Business Acquisition, Mac Fasteners [Domain]
Business Acquisition [Line Items]
Net sales																	17,000,000
Business Acquisition - DHF [Domain]
Business Acquisition [Line Items]
Net sales																	12,000,000
CIFAL [Member]
Business Acquisition [Line Items]
Net sales																		9,000,000
Engetran [Member]
Business Acquisition [Line Items]
Net sales																		6,000,000
Trail Com [Member]
Business Acquisition [Line Items]
Net sales																		12,000,000
Business Acquisition, Arminak & Associates [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred																			67,690,000
Business Acquisition, Deferred Purchase Price and Contingent Consideration																			$ 8,490,000	[2]
Business Acquisition, Percentage of Voting Interests Acquired																			70.00%

[1] Deferred/contingent consideration includes approximately $9.8 million of both short-term and long-term deferred purchase price, based on set amounts and fixed payment schedules per the purchase agreement, and an additional $2.6 million of contingent consideration to be paid based on a multiple of future earnings, as defined.

[2] The contingent consideration represented the Company's best estimate, based on its review, at the time of purchase, of the underlying potential obligations estimated at a range of $8 million to $9 million, of certain Seller tax-related liabilities for which the Company indemnified the Sellers as part of the purchase agreement. During 2012, the Company paid $4.9 million of additional purchase price related to the contingent consideration. No additional amounts were paid during 2013 or 2014. The remaining liability range of $3.1 million to $4.1 million continues to represent the Company's best estimate of the remaining potential obligation at December 31, 2014