Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 23,733	$ 86,197
Receivables:
Trade, net of allowance for doubtful accounts	116,352	106,084
Unbilled receivables	35,140	31,512
Insurance recoveries	6,518	5,470
Income taxes	834	2,168
Deferred income taxes	11,058	15,433
Inventory	12,111	11,184
Prepaid expenses and other current assets	13,040	11,564
Total current assets	218,786	269,612
Property and equipment, at cost	1,698,517	1,336,926
Less accumulated depreciation	684,177	542,970
Net property and equipment	1,014,340	793,956
Intangible assets, net of accumulated amortization	43,843	52,680
Goodwill	41,683	41,683
Noncurrent deferred income taxes	5,519	735
Other long-term assets	15,605	14,088
Total assets	1,339,776	1,172,754
Current liabilities:
Accounts payable	83,823	66,440
Current portion of long-term debt	872	872
Deferred revenues	3,880	3,966
Accrued expenses:
Payroll and related employee costs	27,991	29,057
Insurance premiums and deductibles	9,708	10,583
Insurance claims and settlements	6,348	5,470
Interest	12,343	12,283
Other	11,585	11,009
Total current liabilities	156,550	139,680
Long-term debt, less current portion	518,725	418,728
Noncurrent deferred income taxes	108,838	94,745
Other long-term liabilities	7,983	9,156
Total liabilities	792,096	662,309
Commitments and contingencies (Note 11)
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; 62,032,517 and 61,782,180 shares outstanding at December 31, 2012 and 2011, respectively	6,217	6,188
Additional paid-in capital	449,554	442,020
Treasury stock, at cost; 134,612 and 95,409 shares at December 31, 2012 and 2011, respectively	(1,264)	(904)
Accumulated earnings	93,173	63,141
Total shareholders' equity	547,680	510,445
Total liabilities and shareholders' equity	$ 1,339,776	$ 1,172,754