Other Income, Net (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other Income, Net [Abstract]
Management services	$ 400	$ 850	$ 823
Interest income	2,865	1,510	1,382
Franchise taxes	(893)	(754)	(585)
Equity in income of joint ventures	2,890	2,212	3,818
Other	366	653	1,015
Other income, net	$ 5,628	$ 4,471	$ 6,453