Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock-based payment awards
Options granted (in shares)	0	0	0
Stock Options
Options outstanding at beginning of period (in shares)	154
Options canceled (in shares)	(90)
Options outstanding at end of period (in shares)	64	154
Options exercisable (in shares)	64	154
Weighted Average Exercise Price Per Share
Options outstanding at beginning of period (in dollars per share)	$ 19.40
Options canceled (in dollars per share)	15.32
Options outstanding at end of period (in dollars per share)	25.18	$ 19.40
Options exercisable (in dollars per share)	$ 25.18	$ 19.40
Weighted Average Remaining Life
Weighted average remaining life of outstanding options at end of period	2 months 12 days
Weighted average remaining life of exercisable options at end of period	2 months 12 days
Intrinsic value of options exercised during period (n dollars)			$ 0.8
Options exercised during period (in shares)	0	0
Options
Stock-based payment awards
Vesting period	3 years
Options | Maximum
Stock-based payment awards
Expiration period	7 years
Options | First anniversary vesting
Stock-based payment awards
Vesting percentage	33.33%
Vesting period	1 year
Options | Second anniversary vesting
Stock-based payment awards
Vesting percentage	33.33%
Vesting period	1 year
Options | Third anniversary vesting
Stock-based payment awards
Vesting percentage	33.33%
Vesting period	1 year