Acquisitions Acquisitions (Net Assets Acquired) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 01, 2015	Sep. 01, 2015	May 01, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 254,832	$ 254,664				$ 1,137	$ 1,137
SBS [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 6,342
Accounts receivable			124,526
Inventories			115,888
Prepaid expenses and other current assets			26,504
Property and equipment			125,717
Favorable lease agreements			5,050
Other long-term assets			1,302
Accounts payable			(77,062)
Accrued expenses and other liabilities			(40,652)
Unfavorable lease agreements			(4,550)
Current portion of capital lease obligations			(3,275)
Other current liabilities			(6,664)
Long-term debt			(67,713)
Deferred income taxes			(75,006)
Long-term portion of capital lease obligations			(11,612)
Other long-term liabilities			(5,666)
Identifiable net assets acquired			253,541
Goodwill			199,849
Total net assets acquired			453,390
RBI [Member]
Business Acquisition [Line Items]
Accounts receivable				$ 8,343
Inventories				6,702
Prepaid expenses and other current assets				122
Property and equipment				5,524
Accounts payable and other accrued liabilities				(3,058)
Identifiable net assets acquired				57,933
Goodwill				44,417
Total net assets acquired				102,350
VNS [Member]
Business Acquisition [Line Items]
Cash and cash equivalents					$ 2,344
Accounts receivable					19,452
Inventories					10,665
Prepaid expenses and other current assets					952
Property and equipment					11,643
Other long-term assets					59
Accounts payable					(7,464)
Accrued expenses and other liabilities					(4,087)
Deferred income taxes					(4,364)
Identifiable net assets acquired					40,050
Goodwill					9,429
Total net assets acquired					49,479
Customer relationships [Member] | SBS [Member]
Business Acquisition [Line Items]
Intangible assets acquired			129,800
Customer relationships [Member] | RBI [Member]
Business Acquisition [Line Items]
Intangible assets acquired				39,900
Customer relationships [Member] | VNS [Member]
Business Acquisition [Line Items]
Intangible assets acquired					10,000
Trademarks [Member] | SBS [Member]
Business Acquisition [Line Items]
Intangible assets acquired			4,500
Trademarks [Member] | VNS [Member]
Business Acquisition [Line Items]
Intangible assets acquired					$ 850
Non-compete Agreements [Member] | SBS [Member]
Business Acquisition [Line Items]
Intangible assets acquired			$ 6,112
Non-compete Agreements [Member] | RBI [Member]
Business Acquisition [Line Items]
Intangible assets acquired				$ 400