Statements Of Consolidated Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statements Of Consolidated Operations [Abstract]
Revenues	$ 5,289,953	$ 4,952,000	$ 4,269,239
Costs and Expenses
Salaries, wages and employee benefits	2,026,739	2,024,606	1,853,585
Purchased transportation	1,381,267	1,265,848	983,432
Fuel and fuel-related taxes	566,026	464,997	359,037
Other operating expenses	552,842	547,095	495,196
Depreciation and amortization	202,647	192,502	192,411
Maintenance	130,179	123,864	106,776
Rents and leases	116,415	117,312	99,244
Purchased labor	113,929	113,435	67,820
Loss (Gain) from asset impairments and purchase-price adjustment	(10,000)	19,181	134,813
Restructuring charges	1,981	4,990	2,853
Total Costs and Expenses	5,082,025	4,873,830	4,295,167
Operating Income (Loss)	207,928	78,170	(25,928)
Other Income (Expense)
Investment income	920	1,327	2,358
Interest expense	(55,589)	(59,015)	(64,440)
Miscellaneous, net	(5,187)	(3,925)	(2,259)
Total Other Income (Expense)	(59,856)	(61,613)	(64,341)
Income (Loss) Before Income Tax Provision	148,072	16,557	(90,269)
Income Tax Provision	59,629	12,572	17,478
Net Income (Loss)	88,443	3,985	(107,747)
Preferred Stock Dividends			3,189
Net Income (Loss) Applicable to Common Shareholders	$ 88,443	$ 3,985	$ (110,936)
Weighted-Average Common Shares Outstanding
Basic	55,388,297	52,507,320	47,525,862
Diluted	56,101,903	53,169,299	47,525,862
Basic
Net Income (Loss) Applicable to Common Shareholders	$ 1.60	$ 0.08	$ (2.33)
Diluted
Net Income (Loss) Applicable to Common Shareholders	$ 1.58	$ 0.07	$ (2.33)