Stock-Based Compensation - Restricted Stock Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted stock unit activity
Total restricted stock units outstanding, beginning of period (in shares)	1,504,370	1,760,225	2,484,720
Granted (in shares)	1,696,000
Vested (in shares)	(916,315)	(11,175)	(11,935)
Forfeited and cancelled (in shares)	(420,945)	(244,680)	(712,560)
Total restricted stock units outstanding, end of period (in shares)	1,863,110	1,504,370	1,760,225
Weighted - Average Grant Date Fair Value
Total restricted stock units outstanding, beginning of period (in dollars per share)	$ 50.81	$ 52.15	$ 51.16
Granted (in dollars per share)	33.07
Vested (in dollars per share)	53.82	63.49	63.49
Forfeited and cancelled (in dollars per share)	42.56	59.82	48.51
Total restricted stock units outstanding, end of period (in dollars per share)	$ 35.04	$ 50.81	$ 52.15
2019 LTIP
Restricted stock unit activity
Vested (in shares)	0
Restricted Performance Units/Awards
Restricted stock unit activity
Total restricted stock units outstanding, beginning of period (in shares)	1,483,800	1,726,250
Total restricted stock units outstanding, end of period (in shares)	1,755,125	1,483,800	1,726,250
Weighted - Average Grant Date Fair Value
Total restricted stock units outstanding, beginning of period (in dollars per share)	$ 50.64	$ 51.92
Total restricted stock units outstanding, end of period (in dollars per share)	$ 34.89	$ 50.64	$ 51.92