XML 101 R63.htm IDEA: XBRL DOCUMENT v3.8.0.1
Bank Indebtedness - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2017
CAD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
CAD ($)
Dec. 31, 2016
USD ($)
Disclosure of detailed information about financial instruments [Line Items]        
Description of interest rate Advances under the $40.0 million facility are available at the bank’s prime lending rate, U.S. base rate, U.S. LIBOR plus applicable margin, or Banker’s Acceptance plus applicable margin, or in combination, and under the US$15.0 million facility at the bank’s prime lending rate      
40.0 Million Secured Operating Facilities [Member]        
Disclosure of detailed information about financial instruments [Line Items]        
Line of credit borrowing capacity $ 40,000,000   $ 40,000,000  
Line of credit outstanding 0   0  
Letters of credit outstanding $ 20,800,000   $ 22,000,000  
15.0 Million Secured Operating Facilities [Member]        
Disclosure of detailed information about financial instruments [Line Items]        
Line of credit borrowing capacity   $ 15,000,000   $ 15,000,000
Line of credit outstanding   0   0
30.0 Million Operating Facilities [member]        
Disclosure of detailed information about financial instruments [Line Items]        
Line of credit borrowing capacity   30,000,000   30,000,000
Line of credit outstanding   0   0
Letters of credit outstanding   $ 13,300,000   $ 6,500,000