Components of Income (Loss) Before Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income (loss) before income taxes:
Income before income taxes	$ 61,302	$ 76,134	$ 32,522
CANADA
Income (loss) before income taxes:
Foreign	(796)	(2,036)	(1,872)
UNITED STATES
Income (loss) before income taxes:
U.S.	39,356	37,327	20,422
Other Countries
Income (loss) before income taxes:
Foreign	$ 22,742	$ 40,843	$ 13,972