Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 513,527	$ 437,100
Accounts receivable - Trade, net of allowance for uncollectible accounts of $4,000 and $5,152, respectively	163,486	152,233
Unbilled revenue	32,020	26,992
Costs in excess of billing	1,508	6,848
Other current assets	63,579	96,934
Current assets of discontinued operations		84,000
Total current assets	774,120	804,107
Property and equipment	1,858,537	2,051,796
Less accumulated depreciation	(432,170)	(565,921)
Property and equipment, net	1,426,367	1,485,875
Other assets:
Equity investments	162,839	167,599
Goodwill	61,750	62,935
Other assets, net	49,673	49,837
Non-current assets of discontinued operations		816,227
Total assets	2,474,749	3,386,580
Current liabilities:
Accounts payable	91,836	92,398
Accrued liabilities	100,091	161,514
Current maturities of long-term debt	5,247	16,607
Current liabilities of discontinued operations		182,527
Total current liabilities	197,174	453,046
Long-term debt	543,341	1,002,621
Deferred tax liabilities	288,596	359,237
Other non-current liabilities	19,838	5,025
Non-current liabilities of discontinued operations		147,237
Total liabilities	1,048,949	1,967,166
Commitments and contingencies
Shareholders' equity:
Common stock, no par, 240,000 shares authorized, 105,754 and 105,763 shares issued, respectively	932,899	932,742
Retained earnings	505,136	476,310
Accumulated other comprehensive loss	(37,797)	(15,667)
Total controlling interest shareholders' equity	1,400,238	1,393,385
Noncontrolling interests	25,562	26,029
Total equity	1,425,800	1,419,414
Total liabilities and shareholders' equity	$ 2,474,749	$ 3,386,580