Employee Compensation and Benefit Plans - Schedule of Stock Option Activity (Footnote) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, fair value (in dollars per share)	$ 1.49
Stock options which expired unexercised	73,696	4,719,750
Market-based options that have not met performance criteria (in shares)	115,000
Average common stock trading price to determine market condition for options exercise	$ 38.41
Net aggregate intrinsic value of stock options outstanding	$ 0.0
Market-based options outstanding (in shares)	810,939
Market-based options outstanding, exercisable (in shares)	695,939
Weighted average remaining contractual term of options outstanding	4 years 1 month 16 days
Weighted average remaining contractual term of options exercisable	3 years 3 months 12 days
Total fair value of stock options vested and became exercisable	$ 0.6	$ 0.6	$ 0.7
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	33,180	266,990
Stock options granted, exercise price (in dollars per share)	$ 2.17	$ 4.12