Financial Instruments - Narrative (Details) (Interest rate swaps, USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Interest rate swaps
Financial Instruments (Textual) [Abstract]
Notional Amount	$ 75,000
Fixed LIBOR interest rate	1.08%
Derivative instrument, amortized into earnings from accumulated other comprehensive loss (less than)	$ 400	$ 100

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant