Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income	$ 22,167	$ 11,140
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Provision for losses on accounts receivable	199	402
(Reversal) deferral of gain on sales to equity method investee	(30)	45
Depreciation and amortization	13,445	14,087
Deferred income tax expense	1,047	4,735
Income tax expense arising from restricted share vesting and stock options exercised	(84)	(120)
Stock-based compensation expense	1,893	2,594
Income from equity method investment	(6,785)	(2,960)
Gain on disposition of property and equipment	(167)	(923)
Gain on reversal of contingent loss of discontinued operations	0	(3,412)
Gain on investment in available-for-sale securities	0	(63)
Changes in operating assets and liabilities:
Receivables and advances	22,213	(6,917)
Prepaid expenses and other assets	3,028	(1,064)
Inventory and supplies	(408)	(352)
Insurance and claims accrual	(8,306)	(8,739)
Accounts payable and accrued expenses	(8,796)	1,163
Net cash flows provided by operating activities	39,416	9,616
Cash flows from investing activities:
Acquisition of AAT Carriers, Inc., net of cash acquired	(37,000)	0
Other investment	(12)	0
Purchase of available-for-sale securities	0	(33)
Acquisition of property and equipment	(8,690)	(3,907)
Proceeds from disposition of property and equipment	704	13,871
Net cash flows (used) provided by investing activities	(44,998)	9,931
Cash flows from financing activities:
Change in checks outstanding in excess of bank balances	(216)	(646)
Cash dividend	(1,047)	0
Repayments of notes payable	(1,427)	(8,713)
Repayments of finance lease obligations	(1,293)	(633)
Proceeds under revolving credit facility	70,031	216,128
Repayments under revolving credit facility and draw note	(46,899)	(220,651)
Payment of minimum tax withholdings on stock compensation	(35)	(531)
Common stock repurchased	(14,800)	(8,118)
Net cash flows provided (used) by financing activities	4,314	(23,164)
Net change in cash and cash equivalents	(1,268)	(3,617)
Cash and cash equivalents at beginning of period	8,412	8,407
Cash and cash equivalents at end of period	$ 7,144	$ 4,790