CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Operating Activities:
Net income	$ 50,024	$ 26,242
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization expense	24,464	17,727
Deferred income taxes	9,754	15,703
Stock-based compensation and other	8,338	7,240
Changes in assets and liabilities, net of effect of acquisition	2,047	(66,142)
Net cash provided by operating activities	94,627	770
Investing Activities:
Capital expenditures	(43,118)	(58,682)
Payment for business acquisition	0	(55,000)
Proceeds from sale of investment	0	4,250
Net cash used in investing activities	(43,118)	(109,432)
Financing Activities:
Net proceeds from issuances of common stock	1,971	10,775
Debt issuance costs	(3,084)	0
Tax benefit of stock-based compensation	1,161	2,067
Net cash provided by financing activities	48	12,842
Net increase (decrease) in cash and cash equivalents	51,557	(95,820)
Cash and cash equivalents, beginning of period	252,415	372,986
Cash and cash equivalents, end of period	$ 303,972	$ 277,166