Related Party Transactions (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Significant Shareholders [Member]	Dec. 31, 2011 Significant Shareholders [Member]	Dec. 31, 2010 Significant Shareholders [Member]	Dec. 31, 2012 Vorando Realty Trust [Member]	Dec. 31, 2010 Vorando Realty Trust [Member]	Dec. 31, 2009 Vorando Realty Trust [Member]	Dec. 31, 2011 Short-term Debt [Member] NLS Entity [Member]	Dec. 31, 2010 Short-term Debt [Member] NLS Entity [Member]
Related Party Transaction [Line Items]
Interest bearing, non-recourse mortgage notes, related party							$ 7,614	$ 20,077
Rent revenue recognized	842	864	905
Rent expense for corporate headquarters				$ 919	$ 1,281	$ 1,272