Net Income (Loss) per Common Share (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Securities Included and Excluded from the Computation of Earnings Per Share
Weighted average shares excluded from computation of diluted earnings per share (in shares)	0	1,300,000
Employee Stock Option
Securities Included and Excluded from the Computation of Earnings Per Share
Weighted average number of shares included in computation of diluted earnings per share (in shares)	500,000	0
Restricted Stock
Securities Included and Excluded from the Computation of Earnings Per Share
Weighted average number of shares included in computation of diluted earnings per share (in shares)	200,000	0