Related Party Transactions - Omnibus Agreement (Details) - Omnibus Agreement - Martin Resource Management - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Jan. 01, 2021
Related Party Transaction
Non-compete restriction threshold	$ 5,000,000
Non-compete restriction ownership option opportunity threshold minimum	5,000,000
Non-compete restriction ownership option opportunity threshold minimum with equity limitation	$ 5,000,000
Equity limitation on ownership restriction percentage	20.00%
Approved annual reimbursements for indirect expenses			$ 14,386,000
Indirect expenses reimbursed	$ 3,542,000	$ 4,103,000