Condensed Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 21,401	$ 86,197
Receivables:
Trade, net of allowance for doubtful accounts	117,274	106,084
Unbilled receivables	39,759	31,512
Insurance recoveries	6,464	5,470
Income taxes	146	2,168
Deferred income taxes	16,259	15,433
Inventory	12,220	11,184
Prepaid expenses and other current assets	12,207	11,564
Total current assets	225,730	269,612
Property and equipment, at cost	1,443,614	1,336,926
Less accumulated depreciation	575,126	542,970
Net property and equipment	868,488	793,956
Intangible assets, net of amortization	50,503	52,680
Goodwill	41,683	41,683
Noncurrent deferred income taxes	0	735
Other long-term assets	12,680	14,088
Total assets	1,199,084	1,172,754
Current liabilities:
Accounts payable	85,117	66,440
Current portion of long-term debt	873	872
Prepaid drilling contracts	4,733	3,966
Accrued expenses:
Payroll and related employee costs	23,260	29,057
Insurance premiums and deductibles	10,547	10,583
Insurance claims and settlements	6,464	5,470
Interest	1,789	12,283
Other	11,405	11,009
Total current liabilities	144,188	139,680
Long-term debt, less current portion	418,279	418,728
Noncurrent deferred income taxes	100,701	94,745
Other long-term liabilities	9,375	9,156
Total liabilities	672,543	662,309
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; 61,880,310 shares and 61,782,180 shares outstanding at March 31, 2012 and December 31, 2011, respectively	6,201	6,188
Additional paid-in capital	444,224	442,020
Treasury stock, at cost; 126,036 shares and 95,409 shares at March 31, 2012 and December 31, 2011, respectively	(1,197)	(904)
Accumulated earnings	77,313	63,141
Total shareholders' equity	526,541	510,445
Total liabilities and shareholders' equity	$ 1,199,084	$ 1,172,754