Earnings Per Share - Basic Loss Per Share Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Earnings per share basic:
Income from continuing operations	$ 35,452	$ 45,705	$ 74,985	$ 51,652
Equity earnings of non-consolidated entities	0	1,073	738	1,554
Income from continuing operations and equity earnings of non-consolidated entities	35,452	46,778	75,723	53,206
Undeclared Series A Convertible Preferred Stock dividends	0	0	0	(10,462)
Less net loss attributable to non-controlling interest	(59)	0	(53)	0
Net income attributable to common shareholders	$ 35,511	$ 46,778	$ 75,776	$ 42,744
Weighted average outstanding shares of common stock basic (shares)	105,620,267	104,794,294	105,881,966	89,544,882
Net income per share - basic (usd per share)	$ 0.34	$ 0.45	$ 0.72	$ 0.48