Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 86,197	$ 22,011
Short-term investments	0	12,569
Receivables:
Trade, net of allowance for doubtful accounts	106,084	61,345
Unbilled receivables	31,512	21,423
Insurance recoveries	5,470	4,035
Income taxes	2,168	2,712
Deferred income taxes	15,433	9,867
Inventory	11,184	9,023
Prepaid expenses and other current assets	11,564	8,797
Total current assets	269,612	151,782
Property and equipment, at cost	1,336,926	1,097,179
Less accumulated depreciation	542,970	441,671
Net property and equipment	793,956	655,508
Intangible assets, net of amortization	52,680	21,966
Goodwill	41,683	0
Noncurrent deferred income taxes	735	0
Other long-term assets	14,088	12,087
Total assets	1,172,754	841,343
Current liabilities:
Accounts payable	66,440	26,929
Current portion of long-term debt	872	1,408
Prepaid drilling contracts	3,966	3,669
Accrued expenses:
Payroll and related employee costs	29,057	18,057
Insurance premiums and deductibles	10,583	8,774
Insurance claims and settlements	5,470	4,035
Interest	12,283	7,307
Other	11,009	5,461
Total current liabilities	139,680	75,640
Long-term debt, less current portion	418,728	279,530
Noncurrent deferred income taxes	94,745	80,160
Other long-term liabilities	9,156	9,680
Total liabilities	662,309	445,010
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; 61,782,180 shares and 54,228,170 shares outstanding at December 31, 2011 and December 31, 2010, respectively	6,188	5,425
Additional paid-in capital	442,020	339,105
Treasury stock, at cost; 95,409 shares and 25,380 shares at December 31, 2011 and December 31, 2010, respectively	(904)	(161)
Accumulated earnings	63,141	51,964
Total shareholders' equity	510,445	396,333
Total liabilities and shareholders' equity	$ 1,172,754	$ 841,343