Long-term Compensation Plans - Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) person shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum approved shares of common stock for ESPP (in shares)			5,178,815
Total number of shares issued under ESPP (in shares)	191,560
Persons eligible to participate | person	1,100
Equity compensation expense | $	$ 0.4	$ 0.1	$ 0.0