Supplemental Financial Information - Schedule of Equity Changes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Total Equity - Beginning Balance			$ 882,762
Net Income (Loss)	25,252	(37,858)	33,035	(131,271)
Acquisition of Interest in Discovery			26,448
Acquisition of Noncontrolling Interest in Discovery			(26,448)
Compensation Expense Recognized			7,464
Repurchase of Common Stock			(2,044)
Excess Tax Benefit, Net from Stock-Based Arrangements			842
Other			313
Total Equity - Ending Balance	922,372		922,372
Parent
Total Equity - Beginning Balance			882,762
Net Income (Loss)			33,074
Acquisition of Interest in Discovery			0
Acquisition of Noncontrolling Interest in Discovery			(39)
Compensation Expense Recognized			7,464
Repurchase of Common Stock			(2,044)
Excess Tax Benefit, Net from Stock-Based Arrangements			842
Other			313
Total Equity - Ending Balance	922,372		922,372
Noncontrolling Interest
Total Equity - Beginning Balance			0
Net Income (Loss)			(39)
Acquisition of Interest in Discovery			26,448
Acquisition of Noncontrolling Interest in Discovery			(26,409)
Compensation Expense Recognized			0
Repurchase of Common Stock			0
Excess Tax Benefit, Net from Stock-Based Arrangements			0
Other			0
Total Equity - Ending Balance	$ 0		$ 0