Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net cash provided by operating activities	$ 91,197	$ 100,262
Cash flows from investing activities:
Capital expenditures	(108,073)	(151,688)
Purchases of marketable securities	(120,473)	(91,393)
Sales and maturities of marketable securities	32,740	11,993
Investment in equity method affiliate	0	(5,000)
Net cash used in investing activities	(195,806)	(236,088)
Cash flows from financing activities:
Borrowings under the Credit Facility	45,222	101,765
Payment of deferred financing fees	(4,560)	(6,540)
Restricted cash deposits	(13,362)	(13,494)
Releases from restricted cash	11,009	0
Proceeds from exercise of warrants	0	4
Proceeds from exercise of stock options	173	21
Tax payment upon settlement of stock awards	(37)	0
Payment of Series A Preferred Stock dividends	(3,500)	(3,500)
Proceeds from issuance of Series B Preferred Stock, net of issuance costs	120,753	0
Proceeds from issuance of common stock, net of issuance costs	98,897	0
Net cash provided by financing activities	254,595	78,256
Net increase (decrease) in cash and cash equivalents	149,986	(57,570)
Cash and cash equivalents, beginning of period	186,342	254,418
Cash and cash equivalents, end of period	336,328	196,848
Supplemental cash flow information:
Interest paid	7,271	5,096
Income taxes paid (refunded)	273	(2,927)
Supplemental disclosure of non-cash investing activities:
Property and equipment received but not paid for yet	9,172	10,646
Interest capitalized but not paid	8,706	6,602
Capitalized amortization of deferred financing costs	4,897	4,500
Capitalized paid-in-kind interest	16,542	11,667
Capitalized stock-based compensation	597	657
Series Preferred Stock [Member]
Supplemental disclosure of non-cash financing activities:
Dividends Payable	292	292
Series B Preferred Stock [Member]
Supplemental disclosure of non-cash financing activities:
Dividends Payable	$ 1,102	$ 0