Income Taxes - Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	[1]	Dec. 31, 2017	[1]
Increase in income taxes resulting from:
Total income tax expense	$ 1,900	$ 577		$ 158
MTI
Operating Loss Carryforwards [Line Items]
Expected tax expense	1,116
Increase in income taxes resulting from:
State income taxes, net of federal income tax expense	235
Other non-deductible items	19
Other, net	72
Total income tax expense	$ 1,442

[1] Financial information has been revised to include results attributable to MTI acquired from Martin Resource Management Corporation. See Note 2 – Significant Accounting Policies and Practices.