Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2024

Employee Benefit Plans [Abstract]

Schedule of Expenses Included on Consolidated Statements of Income (Loss) and Consolidated Statements of Comprehensive Income (Loss)

The expenses included on the consolidated statements of income (loss) and the consolidated statements of comprehensive income (loss) were as follows:

For the year ended December 31, 2024	Pension Plans									Other Post-employment Benefit Plans
	Canadian			US			Total			Canadian		US			Total
Consolidated statements of income (loss)
Operating expenses	$	4,349		$	712		$	5,061		$	587	$	—		$	587
Interest expense (income)	$	(1,682	)	$	405		$	(1,277	)	$	939	$	188		$	1,127
Consolidated statements of comprehensive income (loss)
Actuarial (gains) losses on employee benefit plans	$	(19,966	)	$	(3,926	)	$	(23,892	)	$	1,554	$	(290	)	$	1,264

For the year ended December 31, 2023	Pension Plans									Other Post-employment Benefit Plans
	Canadian			US			Total			Canadian		US		Total
Consolidated statements of income (loss)
Operating expenses	$	4,524		$	684		$	5,208		$	466	$	—	$	466
Interest expense	$	(2,294	)	$	567		$	(1,727	)	$	927	$	193	$	1,120
Consolidated statements of comprehensive income (loss)
Actuarial (gains) losses on employee benefit plans	$	4,753		$	(1,224	)	$	3,529		$	1,364	$	157	$	1,521

For the year ended December 31, 2022	Pension Plans									Other Post-employment Benefit Plans
	Canadian			US			Total			Canadian			US			Total
Consolidated statements of income (loss)
Operating expenses	$	6,337		$	540		$	6,877		$	710		$	—		$	710
Interest expense	$	(799	)	$	533		$	(266	)	$	731		$	123		$	854
Consolidated statements of comprehensive income (loss)
Actuarial (gains) losses on employee benefit plans	$	(19,560	)	$	(7,348	)	$	(26,908	)	$	(5,346	)	$	(1,028	)	$	(6,374	)

Schedule of Balance Sheet Obligations, Distributed Between Pension and Other Post-Employment Benefits

The balance sheet obligations, distributed between pension and other post-employment benefits were as follows:

As at December 31,	2024		2023
Included in other long-term liabilities
Pension benefits	$	44,533	$	47,646
Other post-employment benefits		25,941		23,719
Accrued benefit liabilities	$	70,474	$	71,365
Included in other long-term assets
Pension benefits	$	99,554	$	79,637

Schedule of Balance Sheets and the Funded Statuses of the Benefit Plans

The amounts recognized in the balance sheets and the funded statuses of the benefit plans were as follows:

As at December 31, 2024	Pension Plans									Other Post-employment Benefit Plans
	Canadian			US			Total			Canadian		US		Total
Present value of funded obligations	$	314,844		$	60,161		$	375,005		$	—	$	—	$	—
Fair value of plan assets		(374,424	)		(57,168	)		(431,592	)		—		—		—
		(59,580	)		2,993			(56,587	)		—		—		—
Present value of unfunded obligations		1,566			—			1,566			22,395		3,546		25,941
(Pension benefits) accrued benefit liabilities	$	(58,014	)	$	2,993		$	(55,021	)	$	22,395	$	3,546	$	25,941

As at December 31, 2023	Pension Plans									Other Post-employment Benefit Plans
	Canadian			US			Total			Canadian		US		Total
Present value of funded obligations	$	306,251		$	58,546		$	364,797		$	—	$	—	$	—
Fair value of plan assets		(348,170	)		(49,913	)		(398,083	)		—		—		—
		(41,919	)		8,633			(33,286	)		—		—		—
Present value of unfunded obligations		1,295			—			1,295			19,999		3,720		23,719
(Pension benefits) accrued benefit liabilities	$	(40,624	)	$	8,633		$	(31,991	)	$	19,999	$	3,720	$	23,719

Schedule of Changes in the Benefit Obligations and Fair Value of Plan Assets

The changes in the benefit obligations and in the fair value of plan assets were as follows:

As at December 31, 2024	Pension Plans									Other Post-employment Benefit Plans
	Canadian			US			Total			Canadian			US			Total
Change in benefits obligations
Benefit obligation, January 1, 2024	$	307,546		$	58,546		$	366,092		$	19,999		$	3,720		$	23,719
Current service cost		3,890			712			4,602			587			—			587
Interest expense		14,185			2,987			17,172			939			188			1,127
Remeasurements
Actuarial gains arising from plan experience		3,253			(513	)		2,740			—			(177	)		(177	)
Actuarial gains from change in demographic assumptions		—			—			—			—			—			—
Actuarial gains from changes in financial assumptions		—			(3,024	)		(3,024	)		1,554			(113	)		1,441
Benefits paid		(13,215	)		(3,567	)		(16,782	)		(684	)		(378	)		(1,062	)
Contributions by plan participants		862			—			862			—			—			—
Foreign exchange & other		(111	)		5,020			4,909			—			306			306
Benefit obligation, December 31, 2024		316,410			60,161			376,571			22,395			3,546			25,941
Change in fair value of plan assets
Fair value of plan assets, January 1, 2024		(348,170	)		(49,913	)		(398,083	)		—			—			—
Contributions by plan participants		(862	)		—			(862	)		—			—			—
Contributions by employer		(1,364	)		(3,462	)		(4,826)			(684	)		(378	)		(463	)
Transfer to other plans		1,384			—			1,384			—			—			—
Interest income		(15,867	)		(2,582	)		(18,449	)		—			—			—
Benefits paid		13,215			3,567			16,782			684			378			463

As at December 31, 2024	Pension Plans									Other Post-employment Benefit Plans
	Canadian			US			Total			Canadian		US		Total
Remeasurements
Return on plan assets, excluding interest income		(23,219	)		(389	)		(23,608	)		—		—		—
Administrative costs		459			—			459			—		—		—
Foreign exchange & other		—			(4,389	)		(4,389	)		—		—		—
Fair value of plan assets, December 31, 2024		(374,424	)		(57,168	)		(431,592	)		—		—		—
(Pension benefits) accrued benefit liabilities, December 31, 2024	$	(58,014	)	$	2,993		$	(55,021	)	$	22,395	$	3,546	$	25,941

	Pension Plans									Other Post-employment Benefit Plans
As at December 31, 2023	Canadian			US			Total			Canadian			US			Total
Change in benefits obligations
Benefit obligation, January 1, 2023	$	276,757		$	58,835		$	335,592		$	17,888		$	3,857		$	21,745
Current service cost		4,013			684			4,697			466			—			466
Interest expense		14,172			3,010			17,182			927			193			1,120
Remeasurements
Actuarial gains arising from plan experience		6,341			(353	)		5,988			—			122			122
Actuarial gains from change in demographic assumptions		—			—			—			—			—			—
Actuarial gains from changes in financial assumptions		18,911			1,182			20,093			1,364			35			1,399
Benefits paid		(13,768	)		(3,457	)		(17,225	)		(646	)		(403	)		(1,049	)
Contributions by plan participants		928			—			928			—			—			—
Foreign exchange & other		192			(1,355	)		(1,163	)		—			(84	)		(84	)
Benefit obligation, December 31, 2023		307,546			58,546			366,092			19,999			3,720			23,719
Change in fair value of plan assets
Fair value of plan assets, January 1, 2023		(324,069	)		(47,718	)		(371,787	)		—			—			—
Contributions by plan participants		(928	)		—			(928	)		—			—			—
Contributions by employer (net of transfer to other plans)		(487	)		(2,275	)		(2,762	)		(646	)		(403	)		(1,049	)
Interest income		(16,466	)		(2,443	)		(18,909	)		—			—			—
Benefits paid		13,768			3,457			17,225			646			403			1,049

	Pension Plans									Other Post-employment Benefit Plans
As at December 31, 2023	Canadian			US			Total			Canadian		US		Total
Remeasurements
Return on plan assets, excluding interest income		(20,499	)		(2,053	)		(22,552	)		—		—		—
Administrative costs		511			—			511			—		—		—
Foreign exchange & other		—			1,119			1,119			—		—		—
Fair value of plan assets, December 31, 2023		(348,170	)		(49,913	)		(398,083	)		—		—		—
(Pension benefits) accrued benefit liabilities, December 31, 2023	$	(40,624	)	$	8,633		$	(31,991	)	$	19,999	$	3,720	$	23,719

Schedule of Estimated Future Benefit Payments for Defined Benefit Pension Plans and Other Post-Employment Benefit Plans

The estimated future benefit payments for the defined benefit pension plans and other post-employment benefit plans until 2034 are as follows:

	Pension Plans		Other Post- employment Benefit Plans
2025	$	19,925	$	1,353
2026	$	21,098	$	1,401
2027	$	22,016	$	1,447
2028	$	22,849	$	1,490
2029	$	23,526	$	1,567
2030 to 2034	$	123,778	$	8,468

Schedule of Fair Value of the Plan Assets Were Allocated Between the Various Types of Investments

The fair value of the plan assets were allocated as follows between the various types of investments:

As at December 31,	2024	2023
Equity securities
Canada	13.3%	22.0	%
United States	7.9%	13.8	%
International (other than United States)	7.5%	13.6	%
Emerging markets	2.8%	4.7	%
Fixed income instruments
Canada	68.0%	43.8	%
Cash and cash equivalents	0.5%	2.1	%

US Pension Plans

As at December 31,	2024	2023
Equity securities
United States	31.2%	25.9	%
Canada	1.0%	1.0	%
International	17.2%	18.7	%
Fixed income instruments
United States	28.7%	27.4	%
Canada	0.1%	0.1	%
International	3.2%	5.2	%
Other investments
United States	13.4%	14.2	%
Canada	0.3%	0.4	%
International	4.9%	7.1	%

Schedule of Significant Assumptions Adopted in Measuring the Company’s Pension and Other Benefit Obligations

The following are the significant assumptions adopted in measuring the Company’s pension and other benefit obligations:

	Canadian			US
As at December 31,	2024	2023		2024	2023
Actuarial benefit obligation
Discount rate	4.65%	5.15	%	5.60%	5.10	%
Benefit costs for the year ended
Discount rate	4.65%	5.20	%	5.10%	5.30	%
Future salary growth	2.50%	2.50	%	N/A	N/A

Schedule of Other Post-Employment Benefit Plans

Other Post-employment Benefit Plans

As at December 31,	Canadian		US
	2024	2023	2024		2023
Benefit costs for the year ended
Discount rate	4.65%	5.20%	5.60	%	5.30	%
Health care cost trend rate	6.04%	4.04% to 6.04%	N/A		N/A
Other medical trend rates	4.00% to 5.11%	4.00% to 5.11%	N/A		N/A

Schedule of Impact on Defined Benefit Obligation from One Percent Increase or Decrease Change in Assumptions

Pension plans

As at December 31, 2024	Canadian				US
	1% increase		1% decrease		1% increase			1% decrease
Discount rate	$	(34,758)	$	42,597	$	(5,288	)	$	6,238
Future salary growth	$	(3,988)	$	4,466	$	N/A		$	N/A

As at December 31, 2023	Canadian						US
	1% increase			1% decrease			1% increase			1% decrease
Discount rate	$	(35,279	)	$	40,962		$	(5,472	)	$	6,504
Future salary growth	$	3,676		$	(5,305	)		N/A			N/A

Other Post-employment Benefit Plans

	Canadian						US
As at December 31, 2024	1% increase			1% decrease			1% increase			1% decrease
Discount rate	$	(2,714	)	$	3,360		$	(227	)	$	256
Medical and dental trend rates	$	2,074		$	(1,755	)	$	N/A		$	N/A

	Canadian						US
As at December 31, 2023	1% increase			1% decrease			1% increase			1% decrease
Discount rate	$	(2,300	)	$	2,842		$	(241	)	$	273
Medical and dental trend rates	$	476		$	(456	)		N/A			N/A