Contractual interest rate for funds borrowed, under the debt agreement.

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(a)(1))

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

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Debit and Credit Agreements (Parenthetical) (Details)											3 Months Ended		9 Months Ended
Debit and Credit Agreements (Parenthetical) (Details)	Sep. 30, 2014 7.33% weighted-average fixed rate notes	Dec. 31, 2013 7.33% weighted-average fixed rate notes	Sep. 30, 2014 6.51% weighted-average fixed rate notes	Dec. 31, 2013 6.51% weighted-average fixed rate notes	Sep. 30, 2014 9.78% notes	Dec. 31, 2013 9.78% notes	Sep. 30, 2014 5.58% weighted-average fixed rate notes	Dec. 31, 2013 5.58% weighted-average fixed rate notes	Sep. 30, 2014 3.65% weighted-average fixed rate notes	Dec. 31, 2013 3.65% weighted-average fixed rate notes	Sep. 30, 2014 Revolving credit facility	Sep. 30, 2013 Revolving credit facility	Sep. 30, 2014 Revolving credit facility	Sep. 30, 2013 Revolving credit facility
Debt
Long-term debt, weighted average interest rate	7.33%	7.33%	6.51%	6.51%			5.58%	5.58%	3.65%	3.65%
Long-term debt, interest rate, stated percentage					9.78%	9.78%
Weighted-average effective interest rate											2.20%	2.20%	2.20%	2.30%