Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income (loss)	$ 12,204	$ 7,497	$ (7,699)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	28,324	28,463	29,954
Provision for doubtful accounts	480	311	515
Deferred income tax provision (benefit)	2,382	(16,639)	(55)
Share-based compensation	1,164	459	976
Reversal of previously recorded restructuring, impairment and other costs	(639)	0	0
Gain on disposal of assets, net	(2,361)	(773)	(1,116)
Asset impairment	0	0	3,909
Other	(205)	(171)	(47)
Changes in operating assets and liabilities:
Accounts receivable	2,771	2,323	1,949
Inventories, prepaid expenses and other current assets	(426)	117	(979)
Accounts payable and accrued expenses	(3,447)	8,526	(5,945)
Insurance and claims accruals	571	5,603	509
Other long-term assets and liabilities	445	(259)	216
Net cash provided by operating activities	41,263	35,457	22,187
Net Cash Provided by (Used in) Investing Activities [Abstract]
Payments to Acquire Businesses, Gross	(51,440)	0	0
Purchases of property and equipment	(15,019)	(13,976)	(59,751)
Proceeds from sale of property and equipment	10,349	13,875	25,849
Proceeds from operating sale leaseback	5,323	10,980	0
Net cash (used in) provided by investing activities	(50,787)	10,879	(33,902)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Borrowings under long-term debt	84,254	29,991	73,009
Principal payments on long-term debt	(59,859)	(65,633)	(42,866)
Principal payments on capitalized lease obligations	(14,180)	(11,811)	(9,969)
Net change in bank drafts payable	363	(1,398)	240
Excess tax benefit from exercise of stock options	0	0	(135)
Proceeds from capital sale leaseback	0	2,520	19,927
Purchase of common stock	0	0	(28,412)
Issuance of treasury stock	0	(58)	57
Net proceeds or (payments) from stock based awards	(136)	2	(101)
Net cash provided by (used in) financing activities	10,442	(46,387)	11,750
Increase (decrease) in cash and cash equivalents	918	(51)	35
Cash and cash equivalents:
Beginning of year	71	122	87
End of year	989	71	122
Supplemental disclosure of cash flow information
Interest	3,719	3,862	3,382
Income taxes	3,651	175	716
Supplemental schedule of non-cash investing and financing activities
Sales of revenue equipment included in accounts receivable	1,851,000	0	0
Liability incurred for capitalized leases on revenue equipment	$ 42,788,000	$ 2,565,000	$ 29,642,000