Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
OPERATING REVENUES	$ 207,436	$ 191,911
OPERATING EXPENSES:
Labor and benefits	65,757	58,082
Equipment Rents	9,817	10,544
Purchased services	18,031	17,442
Depreciation and amortization	17,633	15,861
Diesel fuel used in operations	21,998	21,421
Diesel fuel sold to third parties	4,990	4,079
Casualties and insurance	5,547	5,438
Materials	6,107	6,583
Net gain on sale of assets	(1,230)	(1,010)
Other operating expenses	17,472	14,268
Total operating expenses	166,122	152,708
INCOME FROM OPERATIONS	41,314	39,203
Interest income	867	775
Interest expense	(8,616)	(9,939)
Other income, net	984	568
Income from continuing operations before income taxes	34,549	30,607
Provision for income taxes	12,305	8,485
Income from continuing operations, net of tax	22,244	22,122
Loss from discontinued operations, net of tax	(3)	0
Net income	$ 22,241	$ 22,122
Basic earnings per share:
Basic earnings per common share from continuing operations	$ 0.55	$ 0.56
Basic loss per common share from discontinued operations	$ 0.00	$ 0.00
Basic earnings per common share	$ 0.55	$ 0.56
Weighted average shares - basic	40,360	39,484
Diluted earnings per share:
Diluted earnings per common share from continuing operations	$ 0.52	$ 0.52
Diluted loss per common share from discontinued operations	$ 0.00	$ 0.00
Diluted earnings per common share	$ 0.52	$ 0.52
Weighted average shares - diluted	43,081	42,545