Summary of Significant Accounting Policies - Components of other operating income (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Operating Income [Abstract]
Property lease guaranty revenue	$ 5,100,000	$ 4,900,000	$ 6,900,000
Interest income	500,000	500,000	600,000
Management fee income	200,000	200,000	200,000
Other	100,000	500,000	200,000
Other operating	$ 5,931,000	$ 6,101,000	$ 7,885,000