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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: 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

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

Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Apr. 30, 2012
Debt Instrument
Long-term debt	$ 1,500,000	$ 924,000
Notes 4.375 Percent [Member]
Debt Instrument
Long-term debt	750,000
Interest rate (as a percent)	4.375%
Line Of Credit [Member]
Debt Instrument
Long-term debt		174,000
Notes 5.875 Percent [Member]
Debt Instrument
Long-term debt	$ 750,000	$ 750,000	$ 750,000
Interest rate (as a percent)	5.875%	5.875%	5.875%