Preferred Stock (Details)	Mar. 18, 2009 item $ / shares shares	Jun. 30, 2016 $ / shares	Dec. 31, 2015 $ / shares
Preferred Stock
Number of preferred share purchase rights declared as dividend for each outstanding share of common stock | item	1
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Number of shares of Series A Junior Participating Preferred Stock that each right entitles the registered holder to purchase | shares	0.001
Par value of Series A Junior Participating Preferred Stock (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Purchase price of Series A Junior Participating Preferred Stock (in dollars per one one-thousandth of a share)	$ 25