Net Earnings (Loss) Per Common Share - Computation of Basic and Diluted Net Earnings Per Common Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Net Earnings (Loss) per Share—Basic:                      
Average common shares outstanding                 32,471 32,171 32,009
Loss from Continuing Operations $ (17,640) $ (5,020) $ (11,580) $ (8,616) $ (2,929) $ (7,790) $ (8,217) $ (7,514) $ (42,856) $ (26,450) $ (68,760)
Total Net Earnings from Discontinued Operations         0 0 0 260 0 260 12,690
Net Loss $ (17,640) $ (5,020) $ (11,580) $ (8,616) $ (2,929) $ (7,790) $ (8,217) $ (7,254) $ (42,856) $ (26,190) $ (56,070)
Net loss from continuing operations - Basic (in dollars per share) $ (0.54) $ (0.15) $ (0.36) $ (0.27) $ (0.09) $ (0.24) $ (0.26) $ (0.23) $ (1.32) $ (0.82) $ (2.15)
Net earnings (loss) from discontinued operations - Basic (in dollars per share         0.00 0.00 0.00 0.01 0.00 0.01 0.40
Net earnings per common share $ (0.54) $ (0.15) $ (0.36) $ (0.27) $ (0.09) $ (0.24) $ (0.26) $ (0.23) $ (1.32) $ (0.81) $ (1.75)
Diluted                      
Average common shares outstanding                 32,471 32,171 32,009
Stock options and awards                 119 512 188
Average common shares assuming dilution                 32,590 32,683 32,197
Loss from Continuing Operations $ (17,640) $ (5,020) $ (11,580) $ (8,616) $ (2,929) $ (7,790) $ (8,217) $ (7,514) $ (42,856) $ (26,450) $ (68,760)
Total Net Earnings from Discontinued Operations         0 0 0 260 0 260 12,690
Net Loss $ (17,640) $ (5,020) $ (11,580) $ (8,616) $ (2,929) $ (7,790) $ (8,217) $ (7,254) $ (42,856) $ (26,190) $ (56,070)
Net loss from continuing operations assuming dilution (in dollars per share) $ (0.54) $ (0.15) $ (0.36) $ (0.27) $ (0.09) $ (0.24) $ (0.26) $ (0.23) $ (1.32) $ (0.82) $ (2.15)
Net earnings (loss) from discontinued operations assuming dilution (in dollars per share)         0.00 0.00 0.00 0.01 0.00 0.01 0.39
Net Earnings (loss) per Share - Assuming Dilution (in dollars per share) $ (0.54) $ (0.15) $ (0.36) $ (0.27) $ (0.09) $ (0.24) $ (0.26) $ (0.23) $ (1.32) $ (0.81) $ (1.75)