Goodwill and Intangible Assets (Narrative) (Details)			12 Months Ended
	Jul. 01, 2017 USD ($)	Jul. 01, 2016 USD ($)	Dec. 31, 2017 USD ($) Segment Units	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Finite-Lived Intangible Assets [Line Items]
Number of reporting units | Units			4
Number of operating Segments | Segment			3
Intangible assets			$ 49,648,000	$ 65,549,000
Non-Cash Impairment Charges			1,600,000
Impairment charges			4,402,000	373,661,000	$ 0
Percentage of Fair Value of Reporting Unit Exceeding its Carrying Value		8.40%
Goodwill	$ 42,800,000		264,826,000	312,541,000	682,810,000
Intangible assets	12,000,000
Goodwill, Impairment Loss	$ 0		4,402,000	372,081,000	0
Amortization of Intangible Assets			$ 9,200,000	8,600,000	8,400,000
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Period of amortization of intangible assets			5 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Period of amortization of intangible assets			12 years
TL
Finite-Lived Intangible Assets [Line Items]
Number of reporting units | Units			1
Intangible assets			$ 36,826,000	41,367,000
Impairment charges			0	159,118,000	0
Goodwill			98,744,000	99,214,000	254,940,000
Goodwill, Impairment Loss			$ 0	157,538,000
LTL
Finite-Lived Intangible Assets [Line Items]
Number of reporting units | Units			1
Intangible assets			$ 750,000	275,000
Impairment charges			0	197,312,000	0
Goodwill			0	0	197,312,000
Goodwill, Impairment Loss			0	197,312,000
Ascent [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets			12,072,000	23,907,000
Impairment charges			4,402,000	17,231,000	0
Goodwill			166,082,000	213,327,000	$ 230,558,000
Goodwill, Impairment Loss		$ 0	$ 4,402,000	$ 17,231,000