Stock-Based Compensation - NSOs (Details) - NSOs - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015		Dec. 28, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, shares		2,847	[1]	2,396	[1]	1,375	[1]	975
Outstanding, Weighted Average Exercise Price		$ 39.00	[1]	$ 45.82	[1]	$ 60.62	[1]	$ 70.90
Outstanding, Weighted Average Fair Value		$ 15.49	[1]	$ 19.15	[1]	$ 30.47	[1]	$ 37.15
Outstanding, Weighted Average Remaining Contractual Term (in years)		6 years 6 months 26 days	[1]	8 years 2 months 12 days	[1]	8 years 3 months 15 days	[1]	9 years
Outstanding, Aggregate Intrinsic Value		$ 21,897	[1]	$ 6,163	[1]	$ 0	[1]	$ 1,164
Grants in period, shares		932		1,363		449
Grants in period, Weighted Average Exercise Price		$ 32.12		$ 30.43		$ 57.91
Grants in period, Weighted Average Fair Value		$ 7.97		$ 7.46		$ 25.81
Exercised in period, shares		(400)				(3)
Exercised in period, Weighted Average Exercise Price		$ 28.31				$ 49.40
Exercised in period, Weighted Average Fair Value		$ 8.54				$ 23.86
Cancelled in period, shares		(87)		(67)		(31)
Cancelled in period, Weighted Average Exercise Price		$ 48.48		$ 60.45		$ 64.01
Cancelled in Period, Weighted Average Fair Value		$ 23.91		$ 30.55		$ 33.63
Forfeitures in period, shares		(447)		(275)		(160)
Forfeitures in period, Weighted Average Exercise Price		$ 29.24		$ 39.89		$ 60.20
Forfeitures in period, Weighted Average Fair Value		$ 8.31		$ 15.04		$ 29.88
Adjustment due to Special Cash Dividend, shares		453				145
Vested and exercisable, shares	[1]	1,187
Vested and exercisable, Weighted Average Exercise Price	[1]	$ 48.48
Vested and exercisable, Weighted Average Fair Value	[1]	$ 23.96
Vested and exercisable, Weighted Average Remaining Contractual Term (in years)	[1]	3 years 11 months 23 days
Vested and exercisable, Aggregate Intrinsic Value	[1]	$ 3,235

[1] (1)The weighted average exercise price and weighted-average fair value of options outstanding as of the end of each reporting period reflect the adjustments to the awards as a result of the respective special cash dividend.