Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Statutory Canadian tax rate	21.00%	35.00%
Deferred tax assets, valuation allowances	$ 12,884	$ 12,811
Valuation allowances recorded on operating losses in certain tax jurisdictions	300	400
Loss carryforwards	3,700	3,700
Capital loss carryforward	5,700	5,700
Tax credits	2,800	2,600
Undistributed earnings of foreign subsidiaries	135,600
Estimated unrecognized income tax and foreign tax liabilities related to undistributed earnings of foreign subsidiaries	300
Unrecognized tax benefits	4,725	4,089	$ 4,962	$ 5,490
Unrecognized tax benefits that will impact tax rate if recognized	3,600	3,400
Unrecognized tax benefit income tax interest and penalties accrued	500	400
Unrecognized tax benefits, income tax penalties and interest expense	100	100
Maximum
Income Taxes [Line Items]
Maximum unrecognized tax benefits expected to be recorded in next twelve months	500	200
CANADA
Income Taxes [Line Items]
Deferred tax assets, valuation allowances	400
Loss carryforwards	$ 3,000	$ 2,700
Operating loss carryforwards expiration year	2033	2032
Capital loss carryforward	$ 5,200	$ 5,200
Tax credits	1,900	1,900
CANADA | Tax Credit That Will Expire In Certain Period
Income Taxes [Line Items]
Tax credits	$ 1,200	$ 1,200
Tax credits, expiration Year	2022	2022
CANADA | Tax Credits That Can Be Carried Forward Indefinitely
Income Taxes [Line Items]
Tax credits	$ 700	$ 700
UNITED STATES
Income Taxes [Line Items]
Loss carryforwards	$ 700	$ 1,000
Operating loss carryforwards expiration year	2037	2036
Tax credits	$ 900	$ 700
UNITED STATES | Tax Credit That Will Expire In Certain Period
Income Taxes [Line Items]
Tax credits	$ 800	$ 600
Tax credits, expiration Year	2033	2032
UNITED STATES | Tax Credits That Can Be Carried Forward Indefinitely
Income Taxes [Line Items]
Tax credits	$ 100	$ 100
UNITED KINGDOM
Income Taxes [Line Items]
Capital loss carryforward	$ 500	$ 500