Business Segments - Revenue Components of Real Estate Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenue from External Customer [Line Items]
Segment revenues	$ 12,953	$ 16,633
Equity in earnings of unconsolidated joint ventures, net	1,455	1,150
Real estate - commercial/industrial
Revenue from External Customer [Line Items]
Segment revenues	2,154	2,279
Operating Segments | Real estate - commercial/industrial
Revenue from External Customer [Line Items]
Segment revenues	2,154	2,279
Equity in earnings of unconsolidated joint ventures, net	1,455	1,150
Income from commercial/industrial and unconsolidated joint ventures	1,930	1,820
Operating Segments | Real estate - commercial/industrial | Pastoria Energy Facility Lease
Revenue from External Customer [Line Items]
Segment revenues	871	898
Operating Segments | Real estate - commercial/industrial | Commercial leases
Revenue from External Customer [Line Items]
Segment revenues	894	684
Operating Segments | Real estate - commercial/industrial | Communication leases
Revenue from External Customer [Line Items]
Segment revenues	196	205
Operating Segments | Real estate - commercial/industrial | Landscaping and other
Revenue from External Customer [Line Items]
Segment revenues	$ 193	$ 492