Organization and Basis of Presentation (Tables)

12 Months Ended

Dec. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of U.S Governmental Revenue

Only the U.S. federal government accounted for 10% or more of our rental revenue, which consists of property rentals and tenant reimbursements, during each of the three years in the period ended December 31, 2017 as follows:

	Year Ended December 31,
(Dollars in thousands)	2017			2016			2015
Rental revenue from the U.S. federal government	$	92,192		$	103,864		$	102,951
Percentage of office segment rental revenue	24.5		%	29.6		%	29.7		%
Percentage of total rental revenue	19.4		%	23.6		%	23.9		%