XML 100 R82.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Pension and other post-retirement benefits - Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status (Detail)
$ in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2019
USD ($)
Dec. 31, 2019
CAD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2018
CAD ($)
Change in plan assets        
Non-current assets (note 11) $ 8,437   $ 3,161  
Pension Plans        
Change in projected benefit obligation        
Projected benefit obligation, beginning of year 484,707   531,694  
Projected benefit obligation assumed from business combination 20,196   0  
Modifications to plans   $ (7,705)   $ 0
Service cost 12,351   15,481  
Interest cost 20,222   19,077  
Actuarial (gain) loss 65,443   (29,986)  
Contributions from retirees 0   0  
Gain on curtailment 0   (1,875)  
Medicare Part D 0   0  
Benefits paid (30,244)   (49,684)  
Projected benefit obligation, end of year 564,970   484,707  
Change in plan assets        
Fair value of plan assets, beginning of year 339,099   403,945  
Plan assets acquired in business combination 8,004   0  
Actual return on plan assets 68,025   (36,987)  
Employer contributions 22,190   21,825  
Medicare Part D subsidy receipts 0   0  
Benefits paid (30,244)   (49,684)  
Fair value of plan assets, end of year 407,074   339,099  
Unfunded status (157,896)   (145,608)  
Non-current assets (note 11) 0   0  
Current liabilities (1,415)   (873)  
Non-current liabilities (156,481)   (144,735)  
Net amount recognized (157,896)   (145,608)  
Other Postretirement Benefit Plans, Defined Benefit        
Change in projected benefit obligation        
Projected benefit obligation, beginning of year 168,325   176,975  
Projected benefit obligation assumed from business combination 11,646   0  
Modifications to plans   $ 0   $ 0
Service cost 4,587   5,791  
Interest cost 7,575   6,727  
Actuarial (gain) loss 33,605   (14,800)  
Contributions from retirees 1,913   1,878  
Gain on curtailment 0   0  
Medicare Part D 414   42  
Benefits paid (8,848)   (8,288)  
Projected benefit obligation, end of year 219,217   168,325  
Change in plan assets        
Fair value of plan assets, beginning of year 115,542   130,487  
Plan assets acquired in business combination 15,688   0  
Actual return on plan assets 25,464   (10,603)  
Employer contributions 8,628   2,026  
Medicare Part D subsidy receipts 414   42  
Benefits paid (6,863)   (6,410)  
Fair value of plan assets, end of year 158,873   115,542  
Unfunded status (60,344)   (52,783)  
Non-current assets (note 11) 8,437   3,161  
Current liabilities (1,168)   (850)  
Non-current liabilities (67,613)   (55,094)  
Net amount recognized $ (60,344)   $ (52,783)