CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock shares authorized (in shares)	140,000,000	140,000,000
Common stock shares issued (in shares)	53,387,591	53,293,449
Common stock shares outstanding (in shares)	51,165,750	51,071,608
Preferred stock par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock shares authorized (in shares)	10,000,000	10,000,000
Preferred stock shares issued (in shares)	0	0
Preferred stock shares outstanding (in shares)	0	0
Treasury stock (in shares)	2,221,841,000	2,221,841,000