Derivatives (Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated OCI gain (loss), net of tax	$ 30,314,000	[1]	$ (3,163,000)	[1]
Period over which gain included in AOCI will be transferred to earnings, months	12
Expected earnings transfer	$ 26,300,000
Expected derivative maturity date	Dec. 31, 2013

[1] Net of taxes.