CONSOLIDATED CONDENSED 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 income	$ 44,484	$ 30,278
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	30,078	27,566
Stock-based compensation expense	9,920	4,624
Excess income tax benefit from stock-based compensation		(358)
Deferred income taxes	(64)	500
Loss on sale of investments	1,786
(Gain) loss on sale of property and equipment	427	(180)
Other long-term liabilities	5,559	8,449
Other non-cash items	1,562	(111)
Changes in other components of working capital	(155,187)	(109,338)
NET CASH USED IN OPERATING ACTIVITIES	(61,435)	(38,570)
Cash Flows from Investing Activities:
Acquisition of property and equipment	(26,730)	(28,127)
Proceeds from sale of property and equipment	1,906	2,359
Proceeds from sale of available-for-sale securities	44,497
Change in restricted cash	(33)	(8,302)
NET CASH PROVIDED (USED) BY INVESTING ACTIVITIES	19,640	(34,070)
Cash Flows from Financing Activities:
Proceeds from debt	717,484	421,550
Repayment of debt	(649,282)	(374,987)
Business acquisition-related payments	(1,260)
Excess income tax benefit from stock-based compensation		358
Issuance of common stock and effect of cashless exercise	(1,531)	341
Debt issuance costs	(3,681)
NET CASH PROVIDED BY FINANCING ACTIVITIES	61,730	47,262
Net Increase/(Decrease) in Cash and Cash Equivalents	19,935	(25,378)
Cash and Cash Equivalents at Beginning of Year	119,923	168,056
Cash and Cash Equivalents at End of Period	139,858	142,678
Supplemental Disclosure of Cash Paid For:
Interest	21,830	21,678
Income taxes	33,668	12,692
Supplemental Disclosure of Non-cash Transactions:
Property and equipment acquired through financing arrangements	27,045	205
Grant date fair value of common stock issued for services	$ 4,480	$ 3,657