Capital Stock (Details) - shares		1 Months Ended		5 Months Ended	6 Months Ended
	Dec. 09, 2016	Jun. 30, 2020	Jun. 30, 2019	May 31, 2020	Jun. 30, 2020
Stock options
Stock-based compensation disclosure
Stock options granted to directors (in shares)					6,686,000
Compensation Policy for Non-Employee Directors | Stock options
Stock-based compensation disclosure
Vesting period					1 year
Stock options granted to directors (in shares)		300,000	108,000
Compensation Policy for Non-Employee Directors | Deferred share units
Stock-based compensation disclosure
Vesting period	1 year
Non-employee directors-initial grant | Stock options
Stock-based compensation disclosure
Annual deferred share units granted		17,000		4,000
Annual stock options grants		50,000		18,000