CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 304,866	$ 247,285
Accounts receivable, net of allowance for doubtful accounts of $1,871 and $3,083, respectively	30,628	23,990
Prepaid expenses and other current assets	18,777	9,978
Total current assets	354,271	281,253
Property and equipment:
Property and equipment	985,084	889,229
Accumulated depreciation and amortization	(643,891)	(578,054)
Total property and equipment, net	341,193	311,175
Deferred tax assets - noncurrent	50,861	5,546
Deposits and other assets ($448 and $442 restricted, respectively)	8,776	8,557
Total assets	755,101	606,531
Current liabilities:
Accounts payable	14,098	14,734
Accrued and other current liabilities	31,465	26,519
Convertible senior notes - current portion, net of discount of $3,099	88,879
Current maturities, capital lease obligations	9,252	10,487
Total current liabilities	143,694	51,740
Senior secured notes including premium of $5,423 and $0, respectively	245,423	175,000
Capital lease obligations, net of current maturities	152,527	127,461
Convertible senior notes, net of discount of $9,494		82,484
Other long term liabilities	19,965	10,067
Total liabilities	561,609	446,752
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value; 75,000,000 shares authorized; 47,334,218 and 47,116,644 shares issued and outstanding, respectively	47	47
Additional paid-in capital	508,256	497,349
Accumulated other comprehensive income	2,136	667
Accumulated deficit	(316,947)	(338,284)
Total stockholders' equity	193,492	159,779
Total liabilities and stockholders' equity	$ 755,101	$ 606,531