Derivatives (Narrative) (Details) (USD $)	1 Months Ended	12 Months Ended
	May 31, 2011	Dec. 31, 2011		Dec. 31, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Number of outstanding interest rate swaps terminated	two
Accumulated OCI gain (loss) net of tax		$ 19,026,000	[1]	$ (6,851,000)	[1]
Expected earnings transfer		18,000,000
Period over which gain included in AOCI will be transferred to earnings, months		12
Expected derivative maturity date		Dec. 01, 2013
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated OCI gain (loss) net of tax		0	[1]	(996,000)	[1]
Interest Rate Swaps [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Increase in interest expenses	1,500,000
Expense capitalized	1,100,000

[1] Net of taxes.