Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 625,650		$ 437,100
Accounts receivable - Trade, net of allowance for uncollectible accounts of $5,154 and $5,152, respectively	142,793		152,233
Unbilled revenue	29,392		26,992
Costs in excess of billing	5,438		6,848
Other current assets	61,189		96,934
Current assets of discontinued operations			84,000
Total current assets	864,462		804,107
Property and equipment	2,115,321		2,051,796
Less accumulated depreciation	(582,594)		(565,921)
Property and equipment, net	1,532,727		1,485,875
Other assets:
Equity investments	165,452		167,599
Goodwill	61,732		62,935
Other assets, net	41,958		49,837
Non-current assets of discontinued operations			816,227
Total assets	2,666,331		3,386,580
Current liabilities:
Accounts payable	100,553		92,398
Accrued liabilities	122,024		161,514
Income tax payable	35,797
Current maturities of long-term debt	10,247	[1]	16,607
Current liabilities of discontinued operations			182,527
Total current liabilities	268,621		453,046
Long-term debt	687,461	[1]	1,002,621
Deferred tax liabilities	290,102		359,237
Other non-current liabilities	14,976		5,025
Non-current liabilities of discontinued operations			147,237
Total liabilities	1,261,160		1,967,166
Commitments and contingencies
Shareholders' equity:
Common stock, no par, 240,000 shares authorized, 105,939 and 105,763 shares issued, respectively	935,463		932,742
Retained earnings	477,925		476,310
Accumulated other comprehensive loss	(33,986)		(15,667)
Total controlling interest shareholders' equity	1,379,402		1,393,385
Noncontrolling interests	25,769		26,029
Total equity	1,405,171		1,419,414
Total liabilities and shareholders' equity	$ 2,666,331		$ 3,386,580

[1] Beginning in March 2018, the holders of these Convertible Senior Notes may require us to repurchase these notes or we may at our own option elect to repurchase notes. These notes will mature in March 2032.