Equity Investees (Consolidated Financial Statements Related to Equity Investees) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Genesis’ share of operating earnings	$ 79,510	$ 71,975	$ 59,255
Amortization of differences attributable to Genesis' carrying value of equity investments	(15,491)	(15,491)	(15,629)
Net equity in earnings	64,019	56,484	43,626
Distributions received	$ 81,061	$ 77,331	$ 71,714