Note 3 - Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue from contract with customer	$ 64,358	$ 79,029
Lease revenue	14,752	14,703
Total revenue	79,110	93,732
Operating Segments [Member]
Total revenue	80,535	95,359
Asphalt Terminalling Services [Member]
Total revenue	25,683	25,803
Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	10,931	11,100
Lease revenue	14,752	14,703
Total revenue	25,683	25,803
Crude Oil Terminalling Services [Member]
Total revenue	3,330	3,871
Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	3,330	3,573
Lease revenue
Total revenue	3,330	3,573
Crude Oil Pipeline Services [Member]
Total revenue	47,554	61,523
Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer	47,554	61,523
Lease revenue
Total revenue	47,554	61,523
Crude Oil Trucking Services [Member]
Total revenue	3,968	4,162
Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer	2,543	2,833
Lease revenue
Total revenue	2,543	2,833
Third Party [Member]
Lease revenue	9,831	9,763
Third Party [Member] | Asphalt Terminalling Services [Member]
Lease revenue	9,831	9,763
Related Party [Member]
Lease revenue	4,921	4,940
Related Party [Member] | Asphalt Terminalling Services [Member]
Lease revenue	4,921	4,940
Fixed Storageand Throughput Revenue [Member] | Third Party [Member]
Revenue from contract with customer	8,105	8,052
Fixed Storageand Throughput Revenue [Member] | Third Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	5,246	4,983
Fixed Storageand Throughput Revenue [Member] | Third Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	2,859	3,069
Fixed Storageand Throughput Revenue [Member] | Third Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Fixed Storageand Throughput Revenue [Member] | Third Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Fixed Storageand Throughput Revenue [Member] | Related Party [Member]
Revenue from contract with customer	3,106	2,931
Fixed Storageand Throughput Revenue [Member] | Related Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	3,106	2,848
Fixed Storageand Throughput Revenue [Member] | Related Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Fixed Storageand Throughput Revenue [Member] | Related Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer		83
Fixed Storageand Throughput Revenue [Member] | Related Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Variable Throughput Revenue [Member] | Third Party [Member]
Revenue from contract with customer	472	507
Variable Throughput Revenue [Member] | Third Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	1	3
Variable Throughput Revenue [Member] | Third Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	471	504
Variable Throughput Revenue [Member] | Third Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Variable Throughput Revenue [Member] | Third Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Variable Reimbursement Revenue [Member] | Third Party [Member]
Revenue from contract with customer	1,607	1,996
Lease revenue	604	534
Variable Reimbursement Revenue [Member] | Third Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	1,607	1,996
Lease revenue	604	534
Variable Reimbursement Revenue [Member] | Third Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Lease revenue
Variable Reimbursement Revenue [Member] | Third Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Lease revenue
Variable Reimbursement Revenue [Member] | Third Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Lease revenue
Variable Reimbursement Revenue [Member] | Related Party [Member]
Revenue from contract with customer	971	1,288
Lease revenue	121	161
Variable Reimbursement Revenue [Member] | Related Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer	971	1,270
Lease revenue	121	161
Variable Reimbursement Revenue [Member] | Related Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Lease revenue
Variable Reimbursement Revenue [Member] | Related Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer		18
Lease revenue
Variable Reimbursement Revenue [Member] | Related Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Lease revenue
Crude Oil Transportation Revenue [Member] | Third Party [Member]
Revenue from contract with customer	3,045	5,331
Crude Oil Transportation Revenue [Member] | Third Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Crude Oil Transportation Revenue [Member] | Third Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Crude Oil Transportation Revenue [Member] | Third Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer	502	2,498
Crude Oil Transportation Revenue [Member] | Third Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer	2,543	2,833
Crude Oil Product Sales Revenue [Member] | Third Party [Member]
Revenue from contract with customer	47,052	58,924
Crude Oil Product Sales Revenue [Member] | Third Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Crude Oil Product Sales Revenue [Member] | Third Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Crude Oil Product Sales Revenue [Member] | Third Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Revenue from contract with customer	47,052	58,924
Crude Oil Product Sales Revenue [Member] | Third Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Revenue from contract with customer
Fixed Lease Revenue [Member] | Third Party [Member]
Lease revenue	9,227	9,229
Fixed Lease Revenue [Member] | Third Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Lease revenue	9,227	9,229
Fixed Lease Revenue [Member] | Third Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Lease revenue
Fixed Lease Revenue [Member] | Third Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Lease revenue
Fixed Lease Revenue [Member] | Third Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Lease revenue
Fixed Lease Revenue [Member] | Related Party [Member]
Lease revenue	4,800	4,779
Fixed Lease Revenue [Member] | Related Party [Member] | Asphalt Terminalling Services [Member] | Operating Segments [Member]
Lease revenue	4,800	4,779
Fixed Lease Revenue [Member] | Related Party [Member] | Crude Oil Terminalling Services [Member] | Operating Segments [Member]
Lease revenue
Fixed Lease Revenue [Member] | Related Party [Member] | Crude Oil Pipeline Services [Member] | Operating Segments [Member]
Lease revenue
Fixed Lease Revenue [Member] | Related Party [Member] | Crude Oil Trucking Services [Member] | Operating Segments [Member]
Lease revenue