Stockholder Rights Plan - Additional Information (Details)			12 Months Ended
	Oct. 20, 2017	Jan. 29, 2016 right $ / shares $ / right	Dec. 31, 2017 $ / shares	Oct. 15, 2017 $ / shares	Dec. 31, 2016 $ / shares
Class Of Stock [Line Items]
Number of rights for each outstanding share | right		1
Common stock, par value		$ 0.01	$ 0.01	$ 0.01	$ 0.01
Right to purchase a share of preferred stock			Each right entitled the registered holder to purchase from the Company one one-thousandth of a share of preferred stock, par value $.01 per share.
Preferred stock, par value		$ 0.01	$ 0.01		$ 0.01
Rights expiration date		Jan. 29, 2026
Minimum percentage of common stock for tender offer		9.80%
Exercise price of rights		$ 12
Percentage of market price of common stock		50.00%
Redemption price per right | $ / right		0.01
American Stock Transfer & Trust Company LLC
Class Of Stock [Line Items]
Amended date	Jan. 29, 2016
Rights accelerated expiration date	Oct. 20, 2017
Series A Preferred Stock
Class Of Stock [Line Items]
Right to purchase a share of preferred stock			each holder of a right, except the acquirer, would have been entitled, subject to the Company’s right to redeem or exchange the right, to exercise, at an exercise price of $12, the right to purchase one one-thousandth of a share of the Company’s newly created Series A Participating Preferred Stock
Preferred stock, par value				$ 0.01