Unconsolidated Joint Ventures (Condensed Income Statement Information for the Joint Ventures) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Columbia Property Trust's Share of Net Income (Loss)	$ 2,656	$ 1,771
Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Revenues	55,228	50,036
Net Income (Loss)	3,690	4,838
Columbia Property Trust's Share of Net Income (Loss)	3,815	2,931
Corporate Joint Venture | Market Square Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Revenues	12,690	11,337
Net Income (Loss)	(1,994)	(2,595)
Columbia Property Trust's Share of Net Income (Loss)	(1,017)	(1,323)
Corporate Joint Venture | University Circle Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Revenues	10,924	11,272
Net Income (Loss)	5,715	6,364
Columbia Property Trust's Share of Net Income (Loss)	3,144	3,500
Corporate Joint Venture | 333 Market Street Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Revenues	7,067	7,054
Net Income (Loss)	3,705	3,713
Columbia Property Trust's Share of Net Income (Loss)	2,037	2,042
Corporate Joint Venture | 114 Fifth Avenue Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Revenues	10,428	10,919
Net Income (Loss)	(2,653)	(2,506)
Columbia Property Trust's Share of Net Income (Loss)	(1,314)	(1,240)
Corporate Joint Venture | 1800 M Street Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Revenues	9,937	9,454
Net Income (Loss)	1,752	388
Columbia Property Trust's Share of Net Income (Loss)	964	214
Corporate Joint Venture | 799 Broadway Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Revenues	0	0
Net Income (Loss)	(32)	(526)
Columbia Property Trust's Share of Net Income (Loss)	(16)	(262)
Corporate Joint Venture | Terminal Warehouse
Schedule of Equity Method Investments [Line Items]
Total Revenues	2,307	0
Net Income (Loss)	(3,741)	0
Columbia Property Trust's Share of Net Income (Loss)	(324)	0
Corporate Joint Venture | Real Estate Services Joint Ventures
Schedule of Equity Method Investments [Line Items]
Total Revenues	1,875	0
Net Income (Loss)	938	0
Columbia Property Trust's Share of Net Income (Loss)	$ 341	$ 0