Acquisitions (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Net sales	$ 510,162	$ 416,471	$ 357,287	$ 292,826	$ 311,848	$ 358,314	$ 351,620	$ 289,716	$ 1,576,746	$ 1,311,498	$ 1,210,156
Income from continuing operations before income taxes									(14,520)	28,455	27,928
Goodwill	254,664				$ 1,137				254,664	1,137	1,137	$ 0
Invetory step-up charges									10,285	$ 0	$ 0
SBS [Member]
Business Acquisition [Line Items]
Business Combination, Inventory Adjustment, Net	2,900								2,900
Business Combination, Acquired Receivables, Gross Contractual Amount	129,200								129,200
Business Combination, Acquired Receivables, Fair Value	124,500								$ 124,500
Date of acquisition									Dec. 01, 2015
Net sales									$ 103,600
Income from continuing operations before income taxes									18,600
Goodwill	199,699								199,699
Business Combination, Inventory Adjustment, Gross	13,200								13,200
Invetory step-up charges									$ 10,285
VNS [Member]
Business Acquisition [Line Items]
Date of acquisition									May 01, 2015
Net sales									$ 104,500
Income from continuing operations before income taxes									4,700
Goodwill	9,287								9,287
Business Combination, Purchase Price	47,100								$ 47,100
WBS [Member]
Business Acquisition [Line Items]
Date of acquisition											Nov. 11, 2013
Business Combination, Purchase Price											$ 6,700
RBI [Member]
Business Acquisition [Line Items]
Date of acquisition									Sep. 01, 2015
Net sales									$ 27,000
Income from continuing operations before income taxes									1,200
Goodwill	44,541								44,541
Business Combination, Purchase Price	102,400								$ 102,400
Customer relationships [Member] | SBS [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									16 years 6 months
Intangible assets acquired	129,800								$ 129,800
Customer relationships [Member] | VNS [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									10 years
Intangible assets acquired	10,000								$ 10,000
Customer relationships [Member] | RBI [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									10 years
Intangible assets acquired	39,900								$ 39,900
Trademarks [Member] | SBS [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									4 years 2 months 12 days
Intangible assets acquired	4,500								$ 4,500
Trademarks [Member] | VNS [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									2 years
Intangible assets acquired	850								$ 850
Noncompete Agreements [Member] | SBS [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									1 year
Intangible assets acquired	6,112								$ 6,112
Noncompete Agreements [Member] | RBI [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									3 years
Intangible assets acquired	$ 400								$ 400