Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Jun. 20, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Oct. 31, 2017
Stockholders Equity Note [Line Items]
Dividends declared and paid per share (usd per share)	$ 0.05	$ 0.05	$ 0.45	$ 0.10	$ 0.9
Dividend equivalents paid				$ 0.6	$ 4.1
Common Stock
Stockholders Equity Note [Line Items]
Treasury stock, value, acquired, cost method				$ 7.5	$ 12.7
Repurchased shares for award (shares)				397,580	432,121
Average repurchase price of shares for award (usd per share)				$ 18.99	$ 29.46
Restricted Stock Units
Stockholders Equity Note [Line Items]
Restricted stock units vested and issued as common stock (shares)				1,065,587	1,049,998
Common Stock | Stock Repurchase Program Authorized in September 2017 [Member]
Stockholders Equity Note [Line Items]
Stock repurchase program, authorized amount						$ 285.0
Treasury stock, shares, acquired (shares)				4,886,382
Treasury stock acquired, average cost per share				$ 22.87
Treasury stock, value, acquired, cost method				$ 111.8