Consolidated Balance Sheet (USD $)	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 26,439,000	$ 27,385,000
Receivables:
Trade, net of allowance for doubtful accounts	142,096,000	115,908,000
Unbilled receivables	44,830,000	49,535,000
Insurance recoveries	10,539,000	8,607,000
Income taxes and other	10,847,000	2,310,000
Deferred income taxes	38,472,000	13,092,000
Inventory	14,327,000	13,232,000
Prepaid expenses and other current assets	6,283,000	9,311,000
Total current assets	293,833,000	239,380,000
Property and equipment, at cost	1,807,981,000	1,724,124,000
Less accumulated depreciation	881,590,000	786,467,000
Net property and equipment	926,391,000	937,657,000
Intangible assets, net of accumulated amortization of $38.3 million and $32.8 million at September 30, 2014 and December 31, 2013, respectively	26,291,000	32,269,000
Noncurrent deferred income taxes	3,450,000	1,156,000
Other long-term assets	14,792,000	19,161,000
Total assets	1,264,757,000	1,229,623,000
Current liabilities:
Accounts payable	66,168,000	43,718,000
Current portion of long-term debt	3,672,000	2,847,000
Deferred revenues	3,244,000	699,000
Accrued expenses:
Payroll and related employee costs	33,519,000	30,020,000
Insurance premiums and deductibles	12,029,000	10,940,000
Insurance claims and settlements	10,539,000	8,607,000
Interest	1,293,000	12,275,000
Other	11,015,000	11,727,000
Total current liabilities	141,479,000	120,833,000
Long-term debt, less current portion	460,060,000	499,666,000
Noncurrent deferred income taxes	117,674,000	84,636,000
Other long-term liabilities	4,669,000	6,055,000
Total liabilities	723,882,000	711,190,000
Commitments and contingencies (Note 8)
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; 63,796,447 and 62,534,636 shares outstanding at September 30, 2014 and December 31, 2013, respectively	6,411,000	6,275,000
Additional paid-in capital	470,695,000	456,812,000
Treasury stock, at cost; 316,682 and 219,304 shares at September 30, 2014 and December 31, 2013, respectively	(3,027,000)	(1,895,000)
Accumulated earnings	66,796,000	57,241,000
Total shareholders' equity	540,875,000	518,433,000
Total liabilities and shareholders' equity	$ 1,264,757,000	$ 1,229,623,000