Description of Business and Basis of Presentation (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2014 USD ($)	Dec. 31, 2013
Organization Consolidation And Presentation of Financial Statements
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015	2014	2013
Company's portfolio of real estate assets - Office space (square feet) | ft²	14,770,000
Company's portfolio of real estate assets - Retail space (square feet) | ft²	786,000
Total Assets | $	$ 2,597,803	$ 2,667,330
Callaway [Member]
Organization Consolidation And Presentation of Financial Statements
Total Assets | $	$ 4,600