8.0% Exchangeable Senior Notes due 2016 (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 27, 2013	Nov. 25, 2013	Dec. 19, 2014	Sep. 18, 2014	Jun. 18, 2014	Mar. 20, 2014	Dec. 19, 2013		Sep. 18, 2013	Jun. 25, 2013	May 14, 2013	Dec. 19, 2012	Nov. 29, 2012	Oct. 22, 2012	Jun. 05, 2012	May 01, 2012
Debt Instrument [Line Items]
Interest expense on notes	$ 5,686,664	$ 563,539
Derivative liabilities, at fair value	2,585,184	1,471,607
Dividend declared, amount per share						$ 0.40	$ 0.40	$ 0.40	$ 0.40	$ 0.95	[1]	$ 0.50	$ 0.45	$ 0.22	$ 1.16	$ 0.98	$ 0.89	$ 0.57	$ 0.51
Special Cash Dividend [Member]
Debt Instrument [Line Items]
Dividend declared, amount per share										$ 0.55
Exchangeable Senior Notes Conversion Option [Member]
Debt Instrument [Line Items]
Derivative liabilities, at fair value	1,000,000	1,500,000			1,300,000
Exchangeable Senior Notes [Member]
Debt Instrument [Line Items]
Principal amount	57,500,000
Proceeds from sale of debt					55,300,000
Initial purchasers' discount	2,000,000	3,000,000			1,700,000
Aggregate estimated offering expenses					2,200,000
Stated interest rate	8.00%
Effective annual rate	10.20%
Interest expense on notes	$ 5,700,000	$ 600,000
Maturity date	Nov. 15, 2016
Percentage of shares outstanding issuable upon exchange	20.00%
Number of shares issuable upon exchange	1,779,560
Conversion ratio				54.3103	52.5417
Exchange price					$ 19.03
Dividend threshold requiring adjustment to exchange rate	$ 0.50
Repurchase price	100.00%
Exchangeable Senior Notes [Member] | Maximum [Member]
Debt Instrument [Line Items]
Conversion ratio	60.4229

[1] Comprised of a regular cash dividend of $0.40 per share of common stock and OP unit for the quarter ending December 31, 2013, and an additional special cash dividend of $0.55 per share of its common stock and OP unit. The Company declared the special cash dividend to distribute taxable income from 2013 attributable to the termination of interest rate swap contracts.