CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Operating revenues:
Rental revenue	$ 34,205	$ 30,604	$ 67,307	$ 60,234
Power revenue	14,486	12,939	28,015	25,313
Interconnection revenue	7,053	5,436	13,625	9,091
Tenant reimbursement and other	1,923	1,657	3,811	3,282
Total operating revenues	57,667	50,636	112,758	97,920
Operating expenses:
Property operating and maintenance	15,118	15,274	29,645	29,669
Real estate taxes and insurance	2,304	2,132	4,524	4,146
Depreciation and amortization	16,261	15,947	32,210	31,408
Sales and marketing	3,936	2,581	7,725	4,710
General and administrative	6,177	6,036	13,180	12,388
Rent	4,756	4,691	9,549	9,268
Transaction costs	249	161	254	283
Total operating expenses	48,801	46,822	97,087	91,872
Operating income	8,866	3,814	15,671	6,048
Interest income	2	5	4	7
Interest expense	(783)	(1,309)	(1,222)	(2,327)
Income before income taxes	8,085	2,510	14,453	3,728
Income tax expense	(206)	(662)	(379)	(537)
Net income	7,879	1,848	14,074	3,191
Net income attributable to noncontrolling interests	3,176	1,022	5,438	1,765
Net income attributable to CoreSite Realty Corporation	4,703	826	8,636	1,426
Preferred stock dividends	(2,085)		(4,169)
Net income attributable to common shares	$ 2,618	$ 826	$ 4,467	$ 1,426
Net income per share attributable to common shares:
Basic (in dollars per share)	$ 0.13	$ 0.04	$ 0.22	$ 0.07
Diluted (in dollars per share)	$ 0.12	$ 0.04	$ 0.21	$ 0.07
Weighted average common shares outstanding
Basic (in shares)	20,829,375	20,532,930	20,752,065	20,494,402
Diluted (in shares)	21,445,875	20,914,686	21,412,289	20,801,050