Annual report pursuant to Section 13 and 15(d)

Selected Quarterly Financial Information - Summarizes Selected Quarterly Financial Information (Details)

v3.10.0.1
Selected Quarterly Financial Information - Summarizes Selected Quarterly Financial Information (Details) - USD ($)
3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 29, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jul. 01, 2017
Apr. 01, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Sales                 $ 803,256,000 $ 624,464,000 $ 633,123,000
Gross Profit (sales less cost of products sold) $ 47,672,000 $ 46,320,000 $ 49,572,000 $ 37,132,000 $ 32,153,000 $ 32,493,000 $ 34,150,000 $ 38,317,000 180,696,000 137,113,000 159,467,000
Impairment Loss 0 0 0 0 16,237,000 0 0 0 0 16,237,000 0
Income (Loss) Before Income Taxes 15,594,000 15,580,000 17,182,000 3,926,000 (9,715,000) 8,646,000 10,569,000 15,491,000      
Net Income (Loss) $ 12,485,000 $ 16,999,000 $ 14,025,000 $ 3,294,000 $ (5,653,000) $ 6,060,000 $ 7,685,000 $ 11,587,000 $ 46,803,000 $ 19,679,000 $ 48,424,000
Basic earnings (loss) per share (in usd per share) $ 0.38 $ 0.53 $ 0.43 $ 0.10 $ (0.18) $ 0.19 $ 0.23 $ 0.35 $ 1.45 $ 0.60 $ 1.44
Diluted earnings (loss) per share (in usd per share) $ 0.37 $ 0.52 $ 0.42 $ 0.10 $ (0.18) $ 0.18 $ 0.22 $ 0.33 $ 1.41 $ 0.58 $ 1.40
Product                      
Sales $ 202,917,000 $ 212,674,000 $ 208,606,000 $ 179,059,000 $ 171,318,000 $ 149,636,000 $ 151,114,000 $ 152,396,000 $ 803,256,000 $ 624,464,000 $ 633,123,000