Debt, Financing Arrangements and Leases (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	$ 694,027	$ 693,831
5.95% senior unsecured notes due 2017
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	184,726	184,662
6.05% senior unsecured notes due 2018
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	249,639	249,573
7% senior unsecured notes due 2016
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	174,809	174,754
7.125% unsecured debentures due 2025
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	$ 84,853	$ 84,842

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant