Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Estimated REIT taxable income	$ 73,962	$ 43,988	$ 24,669
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	135,857
Operating Loss Carryforward, Limitations on Use	As a result of its common stock offering in February 2012, the Company incurred an "ownership change" under Section 382 of the Internal Revenue Code ("Section 382").  In general, if a company incurs an ownership change under Section 382, the company's ability to utilize an NOL carryforward to offset its taxable income after any required dividend distributions, becomes limited to a certain amount per year.  Due to the ownership change, the Company's ability to use its NOL is limited to an estimated $13,451 per year.
Operating Loss Carryforward, Expiration Dates	The NOL will begin to expire principally in the years 2020-2024 to the extent it is not used.
Taxable REIT subsidiary [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 4,208