Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Fair value measurements (Textual)
Marketable securities	$ 24,251		$ 90,235
Total impairment charges related to adjustments to property carrying values	21,900	$ 100,000
Impairment charges before noncontrolling interests and income taxes, is included in discontinued operations	100	74,200
Impairment charge on adjustment to property carrying value	17,100	97,800
Impairment of marketable debt securities	800
Impairment Related To Cost Method Investment		$ 2,200
Impairment of other real estate	4,000
Level 1 [Member]
Fair value measurements (Textual)
Marketable securities	22,500		87,700
Level 3 [Member]
Fair value measurements (Textual)
Marketable securities	$ 1,800		$ 2,300