Preferred Stock (Details) - shares	Dec. 31, 2017	Dec. 31, 2016	Feb. 08, 2016
Preferred Stock
Authorized common stock	195,000,000	195,000,000	195,000,000
Authorized preferred stock	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0