Reconciliation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator for basic earnings per share:
Net earnings	$ 4,627	$ 981
Numerator for diluted earnings per share:
Net earnings	4,627	981
Interest expense attributable to convertible notes	454
Net earnings plus interest expense attributable to convertible notes	$ 5,081	$ 981
Denominator for basic earnings per share:
Basic weighted average common shares outstanding during the period	16,025	11,380
Denominator for diluted earnings per share:
Basic weighted average common shares outstanding during the period	16,025	11,380
Net effect of dilutive convertible notes	1,163
Net effect of dilutive stock options and DSU's	234	288
Diluted weighted average common shares	17,422	11,668
Basic (in dollars per share)	$ 0.29	$ 0.09
Diluted (in dollars per share)	$ 0.29	$ 0.08
Stock options
Denominator for diluted earnings per share:
Antidilutive stock options excluded from weighted average share calculations (in shares)	838,000	345,000