(Intangible Assets Acquired from Business Acquisitions) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 2,100	$ 2,100
Intangible assets
Gross Carrying Amount	94,758		$ 94,758
Accumulated Amortization	(31,287)		(29,209)
Net Carrying Value	63,471		65,549
TL
Intangible assets
Gross Carrying Amount	54,973		54,973
Accumulated Amortization	(14,741)		(13,606)
Net Carrying Value	40,232		41,367
LTL
Intangible assets
Gross Carrying Amount	1,358		1,358
Accumulated Amortization	(1,100)		(1,083)
Net Carrying Value	258		275
Ascent
Intangible assets
Gross Carrying Amount	38,427		38,427
Accumulated Amortization	(15,446)		(14,520)
Net Carrying Value	$ 22,981		$ 23,907