Statements Of Consolidated Income (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Statements Of Consolidated Income
Revenues	$ 1,348,549	$ 1,306,263	$ 2,594,176	$ 2,468,174
Costs and Expenses
Salaries, wages and employee benefits	508,874	523,950	1,000,514	1,013,409
Purchased transportation	348,526	344,039	665,516	621,680
Fuel and fuel-related taxes	150,110	122,335	286,137	236,684
Other operating expenses	142,018	140,191	272,700	273,942
Depreciation and amortization	50,540	47,938	100,854	92,964
Maintenance	32,509	32,016	61,981	63,501
Rents and leases	28,730	30,319	56,521	59,051
Purchased labor	27,077	30,043	53,092	54,344
Loss from impairment of intangible assets				2,767
Total Costs and Expenses	1,288,384	1,270,831	2,497,315	2,418,342
Operating Income	60,165	35,432	96,861	49,832
Other Income (Expense)
Investment income	227	325	549	707
Interest expense	(13,923)	(14,688)	(27,842)	(31,088)
Miscellaneous, net	(1,025)	(758)	(2,763)	(2,054)
Total Other Income (Expense)	(14,721)	(15,121)	(30,056)	(32,435)
Income before Income Tax Provision	45,444	20,311	66,805	17,397
Income Tax Provision	16,022	6,448	30,461	7,571
Net Income Available to Common Shareholders	$ 29,422	$ 13,863	$ 36,344	$ 9,826
Weighted-Average Common Shares Outstanding
Basic	55,413,243	51,665,047	55,227,528	50,506,809
Diluted	56,136,065	52,362,407	55,939,330	51,184,703
Basic
Net Income Available to Common Shareholders	$ 0.53	$ 0.27	$ 0.66	$ 0.19
Diluted
Net Income Available to Common Shareholders	$ 0.52	$ 0.26	$ 0.65	$ 0.19