Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Statutory Canadian tax rate		35.00%
Additional income tax provision from revaluation of tax rate		$ 2,800
Valuation allowances recorded on operating losses in certain tax jurisdictions		100	$ 1,300
Capital loss carryforward		300	100
Capital loss carryforward		5,700	5,200
Loss carryforwards		3,700	4,400
Tax credits		2,600	2,300
Undistributed earnings of foreign subsidiaries		98,000
Estimated unrecognized income and foreign tax liabilities related to undistributed earnings of foreign subsidiaries		200
Unrecognized tax benefits		4,089	4,962	$ 5,490	$ 6,274
Unrecognized tax benefits that will impact tax rate if recognized		3,400	4,000
Unrecognized tax benefit income tax interest and penalties accrued		400	1,100
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		200
Utilized Capital Loss Carryforwards
Income Taxes [Line Items]
Capital loss carryforward			400
CANADA
Income Taxes [Line Items]
Adjusted loss carryforward and related valuation allowance			300
Capital loss carryforward		5,200	4,700
Loss carryforwards		$ 2,700	$ 3,100
Operating loss carryforwards expiration year		2032	2031
Tax credits		$ 1,900	$ 1,800
CANADA | Tax Credit That Will Expire In Certain Period
Income Taxes [Line Items]
Tax credits		$ 1,200	$ 1,100
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		$ 1,000	$ 1,300
Operating loss carryforwards expiration year		2036	2035
Tax credits		$ 700	$ 500
UNITED STATES | Tax Credit That Will Expire In Certain Period
Income Taxes [Line Items]
Tax credits		$ 600	$ 400
Tax credits, expiration Year		2032	2031
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
Scenario, Forecast
Income Taxes [Line Items]
Statutory Canadian tax rate	21.00%