Summary of Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Operating Income [Abstract]
Property lease guaranty revenue	$ 4,900,000	$ 6,900,000	$ 7,500,000
Interest income	500,000	600,000	800,000
Management fee income	200,000	200,000	200,000
Other	500,000	200,000	100,000
Other operating	$ 6,109,000	$ 7,907,000	$ 8,583,000