Principal Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Accounting Policies [Abstract]

Schedule Of Allowance For Uncollectible Accounts

(Dollars in thousands)			Additions
	Balance at beginning of period		Charged to expense		Charged to other accounts		Write-offs net of recoveries			Balance at end of period
2012	$	6,951	$	6,358	$	—	$	(3,535	)	$	9,774
2011	$	6,209	$	6,761	$	—	$	(6,019	)	$	6,951
2010	$	3,456	$	7,319	$	—	$	(4,566	)	$	6,209

Schedule Of Allowance For Revenue Adjustments

(Dollars in thousands)			Additions
	Balance at beginning of period		Charged to expense		Charged to other accounts - Revenue		Write-offs			Balance at end of period
2012	$	16,920	$	—	$	77,310	$	(80,414	)	$	13,816
2011	$	14,291	$	—	$	86,853	$	(84,224	)	$	16,920
2010	$	14,454	$	—	$	85,272	$	(85,435	)	$	14,291

Calculation Of Numerator And Denominator In Earnings Per Share

(Dollars in thousands except per share data)	Years ended December 31,
	2012		2011		2010
Numerator:
Net income	$	104,546	$	88,443	$	3,985
Denominator:
Weighted-average common shares outstanding	55,837,574		55,388,297		52,507,320
Stock options and nonvested stock	648,413		713,606		661,979
	56,485,987		56,101,903		53,169,299
Diluted Earnings per Share	$	1.85	$	1.58	$	0.07
Anti-dilutive securities excluded from the computation of diluted EPS	1,801,995		1,878,191		1,582,355

Non-cash Investing and Financing Activities

Non-cash Investing and Financing Activities

Investing and financing activities that are not reported in the statements of consolidated cash flows due to their non-cash nature are summarized below:

(Dollars in thousands)	Years ended December 31,
	2012		2011		2010
Capital lease incurred to acquire revenue equipment	$	—	$	—	$	55,534
Revenue equipment acquired through partial non-monetary exchanges	$	34,759	$	33,463	$	—
Revenue equipment acquired through increase in accrued liabilities	$	14,034	$	—	$	—
Repurchased common stock issued under defined contribution plan	$	—	$	17,307	$	36,763