Business Segments - Revenue Components of Commercial/Industrial Real Estate Segment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue from External Customer [Line Items]
Segment revenues	$ 47,089	$ 63,098	$ 35,513
Real estate - commercial/industrial [Member]
Revenue from External Customer [Line Items]
Segment revenues	9,941	13,746	10,294
Real estate - commercial/industrial [Member] | Commercial leases [Member]
Revenue from External Customer [Line Items]
Segment revenues	6,095	5,450	5,705
Real estate - commercial/industrial [Member] | Grazing leases [Member]
Revenue from External Customer [Line Items]
Segment revenues	1,331	1,087	1,110
Real estate - commercial/industrial [Member] | Land sale [Member]
Revenue from External Customer [Line Items]
Segment revenues	648	4,340	604
Real estate - commercial/industrial [Member] | All other land management ancillary services [Member]
Revenue from External Customer [Line Items]
Segment revenues	$ 1,867	$ 2,869	$ 2,875