CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Data center revenue:
Rental revenue	$ 474,683	$ 419,528	$ 347,275
Total operating revenues	544,392	481,821	400,352
Operating expenses:
Property operating and maintenance	152,357	132,820	107,212
Real estate taxes and insurance	19,239	14,913	14,250
Depreciation and amortization	141,633	129,251	108,652
Sales and marketing	21,023	18,176	17,495
General and administrative	40,090	37,548	35,369
Rent	27,696	24,125	22,631
Transaction costs	75	176	126
Total operating expenses	402,113	357,009	305,735
Operating income	142,279	124,812	94,617
Interest expense	(35,526)	(24,147)	(12,577)
Income before income taxes	106,753	100,665	82,040
Income tax (expense) benefit	10	(174)	(119)
Net income	106,763	100,491	81,921
Net income attributable to noncontrolling interests	28,841	25,636	23,212
Net income attributable to CoreSite Realty Corporation	77,922	74,855	58,709
Preferred stock dividends		(7,924)	(8,338)
Original issuance costs associated with redeemed preferred stock		(4,326)
Net income attributable to common shares	$ 77,922	$ 62,605	$ 50,371
Net income per share attributable to common shares:
Basic (in dollars per share)	$ 2.23	$ 1.85	$ 1.56
Diluted (in dollars per share)	$ 2.22	$ 1.84	$ 1.54
Weighted average common shares outstanding
Basic (in shares)	34,957,244	33,792,759	32,289,414
Diluted (in shares)	35,137,495	34,058,949	32,732,059
Rental Power And Related Revenue
Data center revenue:
Rental revenue	$ 463,086	$ 407,680	$ 338,687
Interconnection Revenue
Data center revenue:
Revenue	69,709	62,293	53,077
Office Light Industrial And Other Revenue
Data center revenue:
Rental revenue	$ 11,597	$ 11,848	$ 8,588