Share-Based Compensation - Stock Options Unvested (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unvested Stock Options
Unvested stock options
Options outstanding at the beginning of the period (in shares)	17,000
Granted (in shares)	138,000
Vested (in shares)	(155,000)
Options outstanding at the end of the period (in shares)		17,000
Weighted-Average Grant-Date Fair Value
Options outstanding at the beginning of the period (in dollars per share)	$ 5.21
Granted (in dollars per share)	1.07
Vested (in dollars per share)	$ 1.53
Options outstanding at the end of the period (in dollars per share)		$ 5.21
Key Officer Director and Managerial Employee Stock Options
Unvested stock options
Granted (in shares)	138,000	171,124
Weighted-Average Grant-Date Fair Value
Granted (in dollars per share)	$ 1.07	$ 1.75	$ 2.86
Total intrinsic value of stock options exercised			$ 5.1
Total fair value of option vested during the period	$ 0.2	$ 0.4	$ 0.5