Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Canadian net operating losses	$ 117,939	$ 115,436
Canadian pool of SR&ED	95,483	94,705
Property, plant and equipment basis differences	110,092	103,877
Tax credit carryforwards	72,238	72,881
Pension, postretirement and other employee benefits	26,533	37,753
Environmental liabilities	38,069	41,218
Deferred interest deductions	25,731	11,388
Other compensation	5,206	4,330
State net operating losses	3,431	4,987
Capitalized costs	9,677	2,259
Other deferred tax assets	21,047	22,641
Total gross deferred tax assets	525,446	511,475
Less: Valuation allowance	(71,353)	(67,644)
Total deferred tax assets, net of valuation allowance	454,093	443,831
Deferred tax liabilities:
Property, plant and equipment basis differences	(118,072)	(105,152)
Intangible assets	(7,069)	(9,245)
Prepaid expenses	(15,847)	(7,059)
Other deferred tax liabilities	(7,962)	(7,741)
Total deferred tax liabilities	(148,950)	(129,197)
Net deferred tax asset	305,143	314,634
Deferred tax assets	322,164	335,119
Deferred tax liabilities	$ (17,021)	$ (20,485)