Earnings Per Share - Diluted 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 diluted:
Net income attributable to common shareholders - basic and diluted	$ 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
Restricted stock units and options to purchase common stock (shares)	2,032,742	4,291,835	2,382,583	4,188,768
Weighted average outstanding shares of common stock diluted (shares)	107,653,009	109,086,129	108,264,549	93,733,650
Net income per share - diluted (usd per share)	$ 0.33	$ 0.43	$ 0.70	$ 0.46