Consolidated and Combined Statements of Operations - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Net sales $ 3,481,914 $ 5,069,762 $ 4,683,349
Cost of products sold (exclusive of depreciation and amortization) 3,188,924 4,755,031 4,554,188
Operating expenses 71,468 62,993 53,273
Selling, general and administrative 94,403 76,420 55,210
Depreciation and amortization 20,342 17,625 16,515
Total operating costs and expenses 3,375,137 4,912,069 4,679,186
Operating income 106,777 157,693 4,163
Other income (expense) 298 (288) 568
Interest income 456 569 604
Interest expense (27,367) (29,651) (30,914)
Income (loss) before income taxes 80,164 128,323 (25,579)
Income tax provision (1,816) (5,509) (4,259)
Net income 78,348 122,814 (29,838)
Predecessor income through October 29, 2013 0 0 (2,734)
(Income) loss attributable to Kildair from October 29, 2013 through December 8th, 2014 (Note 2) 0 (4,080) 2,338
Incentive distributions declared (321) 0 0
Limited partners’ interest in net income (loss) $ 78,027 $ 118,734 $ (30,234)
Net income (loss) per limited partner unit:      
Common—basic $ 3.71 $ 5.88 $ (1.50)
Common—diluted 3.65 5.84 $ (1.50)
Subordinated—basic and diluted $ 3.71 $ 5.88  
Weighted-average units used to compute net income (loss) per limited partner unit:      
Common—basic 10,975,941 10,131,928 10,071,970
Common—diluted 11,141,333 10,195,566 10,071,970
Distribution declared per common and subordinated units $ 1.9800 $ 1.7400 $ 0.2825
Subordinated Unitholders - Affiliated [Member]      
Net income $ 37,338    
Limited partners’ interest in net income (loss)   $ 59,191 $ (15,117)
Net income (loss) per limited partner unit:      
Common—basic $ 3.71 $ 5.88 $ (1.50)
Common—diluted 3.71 5.88 (1.50)
Subordinated—basic and diluted $ 3.71 $ 5.88 $ (1.50)
Weighted-average units used to compute net income (loss) per limited partner unit:      
Subordinated—basic and diluted 10,071,970 10,071,970 10,071,970