Overview (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable	$ 535,705			$ 653,484
Other noncurrent assets	142,845			132,600
Other current liabilities	19,184			3,395
Deferred income taxes	60,551			46,585
Accumulated deficit	(80,257)			$ (50,706)
Revenue, Net	661,609	$ 456,100
Costs of products sold, exclusive of depreciation and amortization shown below	496,132	348,998
General and administrative	26,477	21,712
Income tax expense	23,083	95
Net loss	(33,035)	(10,277)
Net loss attributable to common shareholders	$ (37,867)	$ (10,277)
Basic earnings (loss) per share, Net	$ (0.48)	$ (0.16)
Diluted earnings (loss) per share, Net	$ (0.48)	$ (0.16)
Accumulated Deficit [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss	$ (33,035)
ASU 2017-07 [Member] | General and Administrative Expense [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Operating Results	100
Accounting Standards Update 2014-09 [Member] | Accumulated Deficit [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ 11,500
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable	1,355
Other noncurrent assets	18,009
Other current liabilities	843
Deferred income taxes	5,581
Accumulated deficit	12,940
Revenue, Net	5,886
Costs of products sold, exclusive of depreciation and amortization shown below	3,541
General and administrative	100
Income tax expense	818
Net loss	1,427
Net loss attributable to common shareholders	$ 1,427
Basic earnings (loss) per share, Net	$ 0.02
Diluted earnings (loss) per share, Net	$ 0.02
Accounting Standards Update 2014-09 [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable	$ 534,350
Other noncurrent assets	124,836
Other current liabilities	18,341
Deferred income taxes	54,970
Accumulated deficit	(93,197)
Revenue, Net	655,723
Costs of products sold, exclusive of depreciation and amortization shown below	492,591
General and administrative	26,377
Income tax expense	22,265
Net loss	(34,462)
Net loss attributable to common shareholders	$ (39,294)
Basic earnings (loss) per share, Net	$ (0.50)
Diluted earnings (loss) per share, Net	$ (0.50)