Revenue Impact of ASC 606 in Current Period Income Statement (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	$ 372,033,000	$ 247,739,000
Decrease in Revenue	(2,012,000)
COST OF GOODS SOLD	223,032,000	158,794,000
Increase (Decrease) Cost of Goods Sold	21,000
Gross Profit	149,001,000	$ 88,945,000
Decrease in Gross Profit	(2,033,000)
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	374,045,000
COST OF GOODS SOLD	223,011,000
Gross Profit	$ 151,034,000