Asset Acquisition - Additional Information (Details)		12 Months Ended
	May 06, 2019 USD ($) truck trailer $ / shares shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Schedule of Asset Acquisition [Line Items]
Cash		$ 5,624,000	$ 10,272,000	$ 0
EH Trucking
Schedule of Asset Acquisition [Line Items]
Payments for asset acquisitions	$ 6,447,000
Cash	$ 5,624,000
Number of shares | shares	11,145
Number of tractor trailer trucks | truck	39
Number of trailers | trailer	51
Transaction costs	$ 100,000
Share price (USD per share) | $ / shares	$ 35.15
Liabilities assumed	$ 0
Maximum quarterly payment	146,875
Contingent consideration arrangements, range of outcomes, value, low	0
Contingent consideration arrangements, range of outcomes, value, high	$ 587,500
Contingent consideration, accrual		200,000
EH Trucking | Customer Relationships
Schedule of Asset Acquisition [Line Items]
Useful life	7 years
Amortization of intangible assets		$ 200,000