Income and Partnership Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax provision based on the U.S. federal statutory tax rate	$ (152,913)	$ 45,182	$ 33,893
Partnership (income) loss not subject to corporate income tax	47,631	(14,031)	(16,403)
State and local taxes, net	(20,594)	4,906	5,278
Valuation allowance	3,150	196	2,321
Expired foreign tax credits	2,253	0	0
Tax credits	(426)	(1,026)	(1,300)
Change in U.S. tax law	(17,983)	111	(8,730)
Foreign currency translation (gains) losses	(1,455)	(4,707)	7,949
Nondeductible expenses and other	(56)	28	135
Total (benefit) provision for income taxes	$ (140,393)	$ 30,659	$ 23,143