Components of Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ (38,697)		$ 10,295
Weighted-average shares – basic	15,098		15,042
Effect of dilutive securities	0	[1]	39
Weighted-average shares – diluted	15,098		15,081
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	200

[1] For the three months ended March 31, 2019, approximately 0.2 million potentially dilutive securities, represented by RSUs and PRSUs, had the effect of being anti-dilutive and were excluded from the calculation of diluted earnings per share.