Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	37,171,000	36,926,000
Common stock, shares outstanding (in shares)	34,612,000	34,816,000
Treasury stock, shares held in treasury (in shares)	2,559,000	2,110,000