Acquisitions Schedule of pro forma information (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Business Combinations [Abstract]
Total revenues			$ 671,952	$ 652,150
Net income			68,594	9,689
Net income attributable to Empire State Realty Trust, Inc.			25,448	20,036
Net income attributable to Empire State Realty Trust, Inc. per share - basic and diluted			$ 0.26	$ 0.20
Total revenues since acquisition date	76,989	392,615
Operating expenses since acquisition date	48,538	289,433
Operating income since acquisition date	28,451	103,182
Net income attributable to common stockholders	$ 10,722	$ 35,002