Organization	12 Months Ended
Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Government Properties Income Trust, or the Company, we or us, is a real estate investment trust, or REIT, formed in 2009 under Maryland law. As of December 31, 2017, we wholly owned 108 properties (167 buildings), or our consolidated properties, located in 30 states and the District of Columbia containing approximately 17.5 million rentable square feet and had a noncontrolling ownership interest in two unconsolidated joint ventures that own properties (three buildings) totaling an additional 0.4 million rentable square feet. As of December 31, 2017, we also owned 24,918,421 common shares of beneficial interest, par value $0.01 per share, or approximately 27.8%, of the then outstanding common shares of Select Income REIT, or SIR.

Organization

12 Months Ended

Dec. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Government Properties Income Trust, or the Company, we or us, is a real estate investment trust, or REIT, formed in 2009 under Maryland law.

As of December 31, 2017, we wholly owned 108 properties (167 buildings), or our consolidated properties, located in 30 states and the District of Columbia containing approximately 17.5 million rentable square feet and had a noncontrolling ownership interest in two unconsolidated joint ventures that own properties (three buildings) totaling an additional 0.4 million rentable square feet. As of December 31, 2017, we also owned 24,918,421 common shares of beneficial interest, par value $0.01 per share, or approximately 27.8%, of the then outstanding common shares of Select Income REIT, or SIR.