Fair Value Measurements - Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013
Fair Value Disclosures [Abstract]
Derivative instrument duration range at inception, minimum	1 month
Derivative instrument duration range at inception, maximum	16 months
Line of credit facility, amount outstanding	$ 20.0

Amount borrowed under the credit facility as of the balance sheet date.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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