Long-Term Debt (Senior Notes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended	0 Months Ended	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Jul. 17, 2012 3.60% Senior Notes Due 2022	Sep. 30, 2012 3.60% Senior Notes Due 2022	Jul. 30, 2012 6 5/8% Senior Notes Due 2016	Jul. 31, 2012 6 5/8% Senior Notes Due 2016	Sep. 30, 2012 6 5/8% Senior Notes Due 2016	Sep. 30, 2012 6 5/8% Senior Notes Due 2016	Jul. 17, 2012 Prior to April 15, 2022 3.60% Senior Notes Due 2022	Jul. 17, 2012 On or after April 15, 2022 3.60% Senior Notes Due 2022
Debt Instrument [Line Items]
Senior notes, principal amount issued					$ 250,000
Stated interest rate					3.60%	3.60%	6.625%		6.625%	6.625%
Maturity					2022	2022	2016	2016		2016
Senior notes, principal amount redeemed							250,000
Senior notes, redemption price as percentage of principal amount							102.208%				100.00%	100.00%
Non-operating expense	7,082	0	7,082	0					7,082
Pre-payment premium									5,520
Write-off of debt issuance costs			1,277	0					1,277
Senior notes, original issue discount					1,183
Senior notes, repurchase price as percentage of principal amount upon change of control and below investment grade rating event					101.00%
Senior notes, maximum number of days from change of control for below investment grade rating event					60 days
Senior notes, minimum debt amount guaranteed by subsidiaries						$ 5,000