Acquisition of Gordon Trucking, Inc. Total Purchase Price Consideration (Details) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquisition of Gordon Trucking, Inc [Abstract]
Payments to Acquire Businesses, Gross			$ 115,900,000
Payments to Acquire Intangible Assets			15,000,000
Cash Acquired from Acquisition			(20,000,000)
Payments to Acquire Businesses, Net of Cash Acquired	3,000,000	3,011,000	110,900,000	0
Business Combination, Acquisition Related Costs			148,000,000
Common stock issued (par value of $0.01)			41,100
Total acquisition purchase price			$ 300,000,000