Derivative Instruments (Interest Rate Derivatives) (Details) In Thousands, unless otherwise specified				3 Months Ended
	Mar. 31, 2014 USD ($)		Dec. 31, 2013 JPY (¥)	Mar. 31, 2014 Swap 3 [Member] USD ($)		Mar. 31, 2014 Swap 3 [Member] JPY (¥)
Derivative [Line Items]
Effective Date				Mar. 15, 2009		Mar. 15, 2009
Termination Date				Sep. 15, 2020		Sep. 15, 2020
Current Notional Amount	$ 46,640	[1]		$ 46,640	[1]
Swap Rate (in thousandths)				2.065%		2.065%
Type				Variable-to-Fixed		Variable-to-Fixed
Exchange rate			102.5300			103.2300

[1] Notional amount converted from Yen at March 31, 2014 at a Yen to USD exchange rate of 103.23