Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Loans receivable, from affiliates	$ 0.0	$ 1.4
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	19,310,346	19,877,381
Common stock, shares outstanding	19,310,346	19,877,381