Leases (Tables)

9 Months Ended

Sep. 30, 2012

Leases [Abstract]

Schedule of lease expenses

	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
Ground lease rent expense	$	2,733	$	2,517	$	7,782	$	7,577
Office rent expense	$	225	$	202	$	657	$	624