CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Data center revenue:
Rental revenue	$ 218,060	$ 183,300	$ 149,294
Power revenue	111,541	89,495	71,227
Interconnection revenue	53,077	44,234	35,355
Tenant reimbursement and other	9,086	8,295	8,702
Office, light-industrial and other revenue	8,588	7,968	7,842
Total operating revenues	400,352	333,292	272,420
Operating expenses:
Property operating and maintenance	107,212	89,805	75,119
Real estate taxes and insurance	14,250	12,144	7,578
Depreciation and amortization	108,652	95,702	80,722
Sales and marketing	17,495	15,930	14,554
General and administrative	35,369	34,179	27,842
Rent	22,631	21,075	20,397
Impairment of internal-use software		322	1,959
Transaction Costs	126	51	62
Total operating expenses	305,735	269,208	228,233
Operating income	94,617	64,084	44,187
Gain (loss) on real estate disposal		36	1,208
Interest income	35	6	6
Interest expense	(12,612)	(7,104)	(5,311)
Income before income taxes	82,040	57,022	40,090
Income tax expense	(119)	(163)	(38)
Net income	81,921	56,859	40,052
Net income attributable to noncontrolling interests	23,212	22,153	17,287
Net income attributable to CoreSite Realty Corporation	58,709	34,706	22,765
Preferred stock dividends	(8,338)	(8,338)	(8,338)
Net income attributable to common shares	$ 50,371	$ 26,368	$ 14,427
Net income per share attributable to common shares:
Basic (in dollars per share)	$ 1.56	$ 1.05	$ 0.68
Diluted (in dollars per share)	$ 1.54	$ 1.03	$ 0.66
Weighted average common shares outstanding
Basic (in shares)	32,289,414	25,218,500	21,161,614
Diluted (in shares)	32,732,059	25,706,568	21,740,707