Hedging Activities - Table (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivative Instruments Gain Loss Line Items
Derivative Instruments Gain Loss Recognized In Other Comprehensive Income Effective Portion Net	$ 272	$ 395	$ 708
Derivative Instruments Gain Loss Reclassified From Accumulated OCI Into Income Effective Portion Net	(392)	(660)	(1,590)
Derivative Instruments Gain Loss Recognized In Income Ineffective Portion And Amount Excluded From Effectiveness Testing Net	$ 0	$ 0	$ 0