CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)
shares in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Net sales $ 500,153 $ 567,080 [1] $ 487,076 [1]
Cost of sales 400,245 458,253 399,721
Gross profit 99,908 108,827 87,355
Selling, general and administrative expenses 71,005 77,952 72,061
Impairment of goodwill and other intangible assets 105,972 0 0
(Gain) loss on sale of property, plant and equipment (2,644) 161 (10)
Restructuring charges 2,087 2,114 1,832
(Loss) income from operations (76,512) 28,600 [1] 13,472 [1]
Interest expense (6,662) (7,588) (3,978)
Interest income and other, net 622 4,720 276
(Loss) earnings before (benefit) provision for income taxes (82,552) 25,732 9,770
(Benefit) provision for income taxes (17,718) 6,535 1,167
Net (loss) earnings available to common shareholders (64,834) 19,197 8,603
Class A [Member]      
Net (loss) earnings available to common shareholders $ (11,408) $ 3,331 $ 1,492
Net (loss) earnings per common share:      
Common shares - basic and diluted (in dollars per share) $ (5.25) $ 1.53 $ 0.69
Weighted-average shares outstanding:      
Common shares - basic and diluted (in shares) 2,175 2,175 2,175
Dividends paid per common share:      
Common shares (in dollars per share) $ 0.24 $ 0.24 $ 0.24
Class B [Member]      
Net (loss) earnings available to common shareholders $ (53,426) $ 15,866 $ 7,111
Net (loss) earnings per common share:      
Common shares - basic and diluted (in dollars per share) $ (5.48) $ 1.64 $ 0.75
Weighted-average shares outstanding:      
Common shares - basic and diluted (in shares) 9,749 9,698 9,491
Dividends paid per common share:      
Common shares (in dollars per share) $ 0.28 $ 0.28 $ 0.28
[1] (Revised)