Income and Partnership Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Compensation	$ 5,800	$ 9,817
Accrued expenses	5,408	3,864
Foreign tax credits	8,765	7,439
Tax attribute carryforwards	13,224	2,101
Derivatives	9,771	5,141
Foreign currency	5,318	6,230
Deferred revenue	10,012	2,402
Deferred tax assets	58,298	36,994
Valuation allowance	(9,755)	(6,606)
Net deferred tax assets	48,543	30,388
Deferred tax liabilities:
Property	(68,256)	(95,087)
Intangibles	(19,882)	(17,347)
Deferred tax liabilities	(88,138)	(112,434)
Net deferred tax liability	$ (39,595)	$ (82,046)