Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly financial information [Line Items]
Revenues	$ 242,638	$ 237,052	$ 245,768	$ 238,855	$ 266,716	$ 247,209	$ 259,658	$ 239,887					$ 964,313	$ 1,013,470	$ 505,492
Gross profit	78,004	74,474	81,917	74,414	90,012	80,077	84,955	70,159					308,809	325,203	172,674
Net income	$ 1,556	$ (112,337)	$ (18,520)	$ (4,634)	$ (21,004)	$ (6,841)	$ 5,902	$ (17,441)					$ (133,935)	$ (39,384)	$ 11,789
Basic	$ 0.08	$ (5.64)	$ (0.93)	$ (0.23)	$ (1.06)	$ (0.34)	$ 0.30	$ (0.88)					$ (6.73)	$ (1.99)	$ 0.71
Earnings (loss) per common share: Diluted	$ 0.08	$ (5.64)	$ (0.93)	$ (0.23)	$ (1.06)	$ (0.34)	$ 0.30	$ (0.88)					$ (6.73)	$ (1.99)	$ 0.70
Dividends paid per common share									$ 0	$ 0	$ 0	$ 0