CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	199,300,000.0	199,300,000.0
Common stock issued (in shares)	105,200,000	103,700,000
Common stock outstanding (in shares)	88,000,000	86,500,000
Treasury stock at cost (in shares)	17,200,000	17,200,000