Goodwill and Intangible Assets (Goodwill acquired in business combination by reportable segment) (Details) - USD ($)			12 Months Ended
	Jul. 01, 2017	Jul. 01, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill impairment loss, beginning balance				$ 0
Adjustments to goodwill for purchase accounting			$ (470,000)	1,812,000
Goodwill, Impairment Loss	$ 0		4,402,000	372,081,000	$ 0
Goodwill, Disposed of During Period			42,843,000
Goodwill impairment loss, ending balance			376,483,000		0
Goodwill, Impairment Loss, Net of Tax			4,402,000	372,081,000
Goodwill, Ending Balance	$ 42,800,000		264,826,000	312,541,000	682,810,000
TL
Goodwill [Roll Forward]
Goodwill impairment loss, beginning balance				0
Adjustments to goodwill for purchase accounting			(470,000)	1,812,000
Goodwill, Impairment Loss			0	157,538,000
Goodwill, Disposed of During Period			0
Goodwill impairment loss, ending balance			157,538,000		0
Goodwill, Impairment Loss, Net of Tax			0	157,538,000
Goodwill, Ending Balance			98,744,000	99,214,000	254,940,000
LTL
Goodwill [Roll Forward]
Goodwill impairment loss, beginning balance				0
Adjustments to goodwill for purchase accounting			0	0
Goodwill, Impairment Loss			0	197,312,000
Goodwill, Disposed of During Period			0
Goodwill impairment loss, ending balance			197,312,000		0
Goodwill, Impairment Loss, Net of Tax			0	197,312,000
Goodwill, Ending Balance			0	0	197,312,000
Ascent [Member]
Goodwill [Roll Forward]
Goodwill impairment loss, beginning balance				0
Adjustments to goodwill for purchase accounting			0	0
Goodwill, Impairment Loss		$ 0	4,402,000	17,231,000
Goodwill, Disposed of During Period			42,843,000
Goodwill impairment loss, ending balance			21,633,000		0
Goodwill, Impairment Loss, Net of Tax			4,402,000	17,231,000
Goodwill, Ending Balance			$ 166,082,000	$ 213,327,000	$ 230,558,000