Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash Flows from Operating Activities:
Net income	$ 53,780	$ 6,028
Amounts to reconcile net income to net cash flows provided by operating activities:
Income from discontinued operations, net of taxes	(10)	(21)
Impairment and other charges	132
Provision (benefit) for deferred income taxes	(67,107)	4,479
Depreciation and amortization	32,009	32,434
Amortization of deferred financing costs	1,165	1,212
Amortization of discount on convertible notes	3,593	3,307
Write-off of deferred financing costs related to senior notes	544
Stock-based compensation expense	2,680	2,356
Excess tax benefit from stock-based compensation	(212)
Changes in:
Trade receivables	(5,402)	(21,036)
Interest receivable	475	551
Accounts payable and accrued liabilities	(74,405)	(18,728)
Other assets and liabilities	5,847	3,320
Net cash flows provided by (used in) operating activities - continuing operations	(46,911)	13,902
Net cash flows provided by operating activities - discontinued operations	49	13
Net cash flows provided by (used in) operating activities	(46,862)	13,915
Cash Flows from Investing Activities:
Purchases of property and equipment	(10,139)	(29,734)
Collection of notes receivable		2,870
Other investing activities	(715)	378
Net cash flows used in investing activities - continuing operations	(10,854)	(26,486)
Net cash flows used in investing activities - discontinued operations
Net cash flows used in investing activities	(10,854)	(26,486)
Cash Flows from Financing Activities:
Net borrowings (repayments) under credit facility	209,000	(15,000)
Early redemption of senior notes	(152,180)
Deferred financing costs paid	(22)
Repurchase of Company stock for retirement	(55,676)
Proceeds from exercise of stock option and purchase plans	4,255	3,232
Excess tax benefit from stock-based compensation	212
Other financing activities, net	(195)	(187)
Net cash flows provided by (used in) financing activities - continuing operations	5,394	(11,955)
Net cash flows provided by financing activities - discontinued operations
Net cash flows provided by (used in) financing activities	5,394	(11,955)
Net change in cash and cash equivalents	(52,322)	(24,526)
Cash and cash equivalents - unrestricted, beginning of period	97,170	44,388
Cash and cash equivalents - unrestricted, end of period	$ 44,848	$ 19,862