Stockholders' Equity (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) vote $ / shares shares	Mar. 31, 2017 USD ($)	Feb. 08, 2017 shares
Accumulated Other Comprehensive Income (Loss) [Line Items]
Common stock shares authorized (in shares)	300,000,000.0
Common stock par value (USD per share) | $ / shares	$ 0.01
Preferred stock authorized shares (in shares)	10,000.00
Preferred stock par or stated value (in dollars per share) | $ / shares	$ 0.01
Common stock, number of votes granted per common share held | vote	1
Treasury stock, shares, acquired (in shares)	600,000
Value of treasury stock acquired | $	$ 40.1
Series A Preferred Stock
Accumulated Other Comprehensive Income (Loss) [Line Items]
Number of shares called by each right			0.001
Performance-based Restricted Stock Units
Accumulated Other Comprehensive Income (Loss) [Line Items]
Value of treasury stock acquired | $	$ 2.9	$ 3.7
Repurchase of shares upon vesting of PRSUs withheld to satisfy tax withholding obligations (in shares)	100,000
February 2016 Program
Accumulated Other Comprehensive Income (Loss) [Line Items]
Remaining shares under share repurchase authorization (in shares)	226,900,000