Acquisition - Additional Information (Detail) $ in Thousands		3 Months Ended		6 Months Ended
	Dec. 09, 2020 USD ($) Carrier	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Business Acquisition [Line Items]
Business acquisition, cash paid	$ 89,800
Post-Closing Activities		$ 100
Revenue		981,320	$ 779,243	$ 1,900,873	$ 1,618,102
Operating income		36,948	$ 20,978	60,999	$ 40,737
Nonstop Delivery, LLC [Member]
Business Acquisition [Line Items]
Business acquisition date	Dec. 09, 2020
Percentage of equity interests acquired	100.00%
Consideration for transaction	$ 105,900
Settlement of accounts receivable due from subsidiary	$ 16,100
Number of network carriers | Carrier	170
Goodwill and other intangible assets tax deductible, period	15 years
Amortization expense of intangible assets		$ 1,000		$ 1,800
Intangible assets, weighted average useful life				14 years 1 month 17 days