Note 1 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Disaggregation of Revenue [Table Text Block]

(in thousands)	Twelve Months Ended
	December 31,
	2018		2017		2016
Total Revenues:
Truckload Segment:
Expedited	$	334,118	$	332,930	$	370,689
Dedicated		247,877		144,845		60,154
Refrigerated		135,189		135,059		170,383
OTR		9,862		-		-
Truckload Revenues		727,046		612,834		601,226
Managed Freight Segment:
Brokerage		114,827		89,042		66,867
Warehouse		16,480		-		-
TMS		14,940		-		-
Shuttle & Switching		7,100		-		-
Factoring		5,062		3,131		2,558
Managed Freight Revenues		158,409		92,173		69,425
Total	$	885,455	$	705,007	$	670,651

Summary of Valuation Allowance [Table Text Block]

Years ended December 31:	Beginning balance January 1,		Additional provisions to (reversal of) allowance			Write-offs and other adjustments			Ending balance December 31,
2018	$	1,456	$	507		$	22		$	1,985
2017	$	1,345	$	454		$	(343	)	$	1,456
2016	$	1,857	$	(241	)	$	(271	)	$	1,345

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

(in thousands except per share data)
	2018		2017		2016
Numerator:
Net income	$	42,503	$	55,439	$	16,835
Denominator:
Denominator for basic income per share – weighted-average shares		18,340		18,279		18,182
Effect of dilutive securities:
Equivalent shares issuable upon conversion of unvested restricted shares		129		93		84
Denominator for diluted income per share adjusted weighted-average shares and assumed conversions		18,469		18,372		18,266
Net income per share:
Basic income per share	$	2.32	$	3.03	$	0.93
Diluted income per share	$	2.30	$	3.02	$	0.92

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

	Twelve Months Ended December 31, 2018
							Balances without
							adoption of Topic
Financial Statement Line Item (in thousands)	As reported			Adjustments				606
Consolidated Balance Sheet
Accounts receivable, net of allowances	$	151,093		$	(1,244	)	$	149,849
Total assets		773,524			(1,244	)		772,280
Accrued expenses		49,503			(277	)		49,226
Deferred income taxes		77,467			(266	)		77,201
Total liabilities		430,382			(543	)		429,839
Retained earnings		200,566			(701	)		199,865
Total stockholders’ equity		343,142			(701	)		342,441
Total liabilities and stockholders’ equity		773,524			(1,244	)		772,280
Consolidated Statement of Operations
Freight revenue		779,729			(234	)		779,495
Total revenue		885,455			(234	)		885,221
Salaries, wages and related expenses		304,447			13			304,460
Revenue equipment rentals and purchased transportation		183,645			(95	)		183,550
Total operating expenses		826,469			(82	)		826,387
Income tax expense (benefit)		15,507			(41	)		15,466
Net income		42,503			(111	)		42,392
Consolidated Statement of Comprehensive Income
Net income		42,503			(111	)		42,392
Comprehensive income		42,414			(111	)		42,303
Consolidated Statement of Cash Flows
Operating Cash Flows
Net income		42,503			(111	)		42,392
Deferred income tax expense (benefit)		13,840			(41	)		13,799
Change in: Receivables and advances		(27,199	)		234			(26,965	)
Change in: Accounts payable and accrued expenses		19,232			(82	)		19,150
Net cash flows provided by operating activities		124,800			-			124,800