CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Income Statement [Abstract]      
Net sales $ 1,911,844 $ 1,839,726 $ 1,566,643
Cost of products sold 1,449,570 1,420,014 1,258,842
Gross profit 462,274 419,712 307,801
Operating expenses:      
Selling, general and administrative expenses 268,714 271,874 224,163
Amortization of intangible assets 25,064 25,306 22,140
Total operating expenses 293,778 297,180 246,303
Operating earnings 168,496 122,532 61,498
Foreign currency gain (loss) 299 (3,166) (992)
Interest expense (72,718) (74,876) (71,269)
Interest income 36 57 83
tax receivable agreement adjustment (60,874) (12,947) 670
Loss on modification or extinguishment of debt (11,747) 0 (21,364)
Income (loss) before benefit from income taxes 23,492 31,600 (31,374)
Benefit from income taxes (51,995) (688) (105)
Net income (loss) $ 75,487 $ 32,288 $ (31,269)
Earnings Per Share, Basic $ 1.11 $ 0.47 $ (0.46)
Earnings Per Share, Diluted $ 1.10 $ 0.47 $ (0.46)
Weighted Average Number of Shares Outstanding, Basic 68,176,801 68,003,564 67,819,046
Weighted Average Number of Shares Outstanding, Diluted 68,324,146 68,106,493 67,819,046