Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Revenue components of commercial/industrial real estate segment
Revenue of commercial/industrial real estate segment	$ 18,741	$ 15,152
Commercial leases [Member]
Revenue components of commercial/industrial real estate segment
Revenue of commercial/industrial real estate segment	4,477	4,129
Oil and Gas [Member]
Revenue components of commercial/industrial real estate segment
Revenue of commercial/industrial real estate segment	10,142	6,725
Mineral revenue [Member]
Revenue components of commercial/industrial real estate segment
Revenue of commercial/industrial real estate segment	1,150	1,095
Grazing leases [Member]
Revenue components of commercial/industrial real estate segment
Revenue of commercial/industrial real estate segment	958	841
Land Sale [Member]
Revenue components of commercial/industrial real estate segment
Revenue of commercial/industrial real estate segment	648	0
All other land management ancillary services [Member]
Revenue components of commercial/industrial real estate segment
Revenue of commercial/industrial real estate segment	$ 1,366	$ 2,362