Consolidated Balance Sheet (USD $)	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 23,711,000	$ 27,385,000
Receivables:
Trade, net of allowance for doubtful accounts	132,215,000	115,908,000
Unbilled receivables	52,156,000	49,535,000
Insurance recoveries	9,717,000	8,607,000
Income taxes and other	6,449,000	2,310,000
Deferred income taxes	32,365,000	13,092,000
Inventory	13,466,000	13,232,000
Prepaid expenses and other current assets	9,390,000	9,311,000
Total current assets	279,469,000	239,380,000
Property and equipment, at cost	1,778,653,000	1,724,124,000
Less accumulated depreciation	855,213,000	786,467,000
Net property and equipment	923,440,000	937,657,000
Intangible assets, net of accumulated amortization of $36.3 million and $32.8 million at June 30, 2014 and December 31, 2013, respectively	28,276,000	32,269,000
Noncurrent deferred income taxes	4,010,000	1,156,000
Other long-term assets	16,236,000	19,161,000
Total assets	1,251,431,000	1,229,623,000
Current liabilities:
Accounts payable	54,735,000	43,718,000
Current portion of long-term debt	429,000	2,847,000
Deferred revenues	3,306,000	699,000
Accrued expenses:
Payroll and related employee costs	29,644,000	30,020,000
Insurance premiums and deductibles	11,575,000	10,940,000
Insurance claims and settlements	9,716,000	8,607,000
Interest	8,744,000	12,275,000
Other	12,104,000	11,727,000
Total current liabilities	130,253,000	120,833,000
Long-term debt, less current portion	493,630,000	499,666,000
Noncurrent deferred income taxes	102,988,000	84,636,000
Other long-term liabilities	4,771,000	6,055,000
Total liabilities	731,642,000	711,190,000
Commitments and contingencies (Note 7)
Shareholders' equity:
Preferred stock, 10,000,000 shares authorized; none issued and outstanding	0	0
Common stock $.10 par value; 100,000,000 shares authorized; 63,101,570 and 62,534,636 shares outstanding at June 30, 2014 and December 31, 2013, respectively	6,342,000	6,275,000
Additional paid-in capital	462,131,000	456,812,000
Treasury stock, at cost; 316,682 and 219,304 shares at June 30, 2014 and December 31, 2013, respectively	(3,027,000)	(1,895,000)
Accumulated earnings	54,343,000	57,241,000
Total shareholders' equity	519,789,000	518,433,000
Total liabilities and shareholders' equity	$ 1,251,431,000	$ 1,229,623,000