Organization	12 Months Ended
Dec. 31, 2012
Organization
Organization	1. Organization CoreSite Realty Corporation (the “Company,” “we,” or “our”) was organized in the state of Maryland on February 17, 2010 and is a fully integrated, self-administered, and self-managed real estate investment trust (“REIT”). Through our controlling interest in CoreSite, L.P. (our “Operating Partnership”), we are engaged in the business of owning, acquiring, constructing and managing technology-related real estate or more commonly referred to as data centers. On September 28, 2010, we closed our initial public offering (the “IPO”) which resulted in the sale of 19,435,000 shares of our common stock at a price per share of $16.00, generating net proceeds to the Company of $285.6 million. As of December 31, 2012, the Company owns a 44.8% common interest in the Operating Partnership. Upon completion of the IPO, our Operating Partnership entered into various formation transactions and acquired 100% of the ownership interests in the entities that owned our Predecessor from certain real estate funds (the “Funds”) affiliated with The Carlyle Group. Our Predecessor includes the limited liability companies which were all wholly owned, directly or indirectly, by CRP Fund V Holdings, LLC. We determined that CRP Fund V Holdings, LLC was the acquirer for accounting purposes and, therefore, interests contributed by CRP Fund V Holdings, LLC in the formation transactions (the Predecessor entities and properties) were recorded at historical cost. The Funds own approximately 55% of the common interest in the Operating Partnership. Additionally, our Operating Partnership acquired 100% of the ownership interests in the entities that owned the CoreSite Acquired Properties from the Funds and their affiliates. The contribution or acquisition of interests in the CoreSite Acquired Properties was accounted for as an acquisition under the acquisition method of accounting and recognized at the estimated fair value of acquired assets and assumed liabilities on the date of the contribution. The financial condition and results of operations for the entities acquired by our Predecessor in connection with the IPO and related formation transactions are only included in the consolidated financial statements since the date of the transactions. Prior to the date of the transactions of September 28, 2010, the consolidated financial statements include only the activities and capital structure of our Predecessor. More specifically, our results of operations for the year ended December 31, 2010 reflect the operations of the consolidated Predecessor entities together with the CoreSite Acquired Properties from the date of their acquisition. Changes in our capital structure that occurred on September 28, 2010, including the acquisition of our Predecessor by our Operating Partnership, are reflected since that date in the financial statements including the allocation of net loss attributable to noncontrolling interest holders and calculations of net loss per share.

1. Organization

CoreSite Realty Corporation (the “Company,” “we,” or “our”) was organized in the state of Maryland on February 17, 2010 and is a fully integrated, self-administered, and self-managed real estate investment trust (“REIT”). Through our controlling interest in CoreSite, L.P. (our “Operating Partnership”), we are engaged in the business of owning, acquiring, constructing and managing technology-related real estate or more commonly referred to as data centers. On September 28, 2010, we closed our initial public offering (the “IPO”) which resulted in the sale of 19,435,000 shares of our common stock at a price per share of $16.00, generating net proceeds to the Company of $285.6 million. As of December 31, 2012, the Company owns a 44.8% common interest in the Operating Partnership.

Upon completion of the IPO, our Operating Partnership entered into various formation transactions and acquired 100% of the ownership interests in the entities that owned our Predecessor from certain real estate funds (the “Funds”) affiliated with The Carlyle Group. Our Predecessor includes the limited liability companies which were all wholly owned, directly or indirectly, by CRP Fund V Holdings, LLC. We determined that CRP Fund V Holdings, LLC was the acquirer for accounting purposes and, therefore, interests contributed by CRP Fund V Holdings, LLC in the formation transactions (the Predecessor entities and properties) were recorded at historical cost. The Funds own approximately 55% of the common interest in the Operating Partnership.

Additionally, our Operating Partnership acquired 100% of the ownership interests in the entities that owned the CoreSite Acquired Properties from the Funds and their affiliates. The contribution or acquisition of interests in the CoreSite Acquired Properties was accounted for as an acquisition under the acquisition method of accounting and recognized at the estimated fair value of acquired assets and assumed liabilities on the date of the contribution.

The financial condition and results of operations for the entities acquired by our Predecessor in connection with the IPO and related formation transactions are only included in the consolidated financial statements since the date of the transactions. Prior to the date of the transactions of September 28, 2010, the consolidated financial statements include only the activities and capital structure of our Predecessor. More specifically, our results of operations for the year ended December 31, 2010 reflect the operations of the consolidated Predecessor entities together with the CoreSite Acquired Properties from the date of their acquisition. Changes in our capital structure that occurred on September 28, 2010, including the acquisition of our Predecessor by our Operating Partnership, are reflected since that date in the financial statements including the allocation of net loss attributable to noncontrolling interest holders and calculations of net loss per share.