Debt (Details) (USD $)	0 Months Ended		1 Months Ended	12 Months Ended								12 Months Ended				0 Months Ended			0 Months Ended
	Sep. 07, 2012	Jan. 10, 2012	Oct. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Oct. 10, 2012	Mar. 29, 2012	Mar. 07, 2011	Jan. 19, 2011	Jan. 19, 2011 Subject to meeting specified requirements and obtaining additional commitments	Dec. 31, 2013 Line of Credit	Jan. 09, 2014 Subsequent Event	Jan. 09, 2014 Subsequent Event Line of Credit	Jan. 09, 2014 Revolving Credit Facility Subsequent Event	Jan. 09, 2014 Revolving Credit Facility Subsequent Event Line of Credit Extension_Option	Feb. 21, 2014 Term Loan Subsequent Event	Jan. 09, 2014 Term Loan Subsequent Event	Jan. 09, 2014 Term Loan Subsequent Event Line of Credit Extension_Option	Jan. 09, 2014 LIBOR Subsequent Event Line of Credit	Jan. 09, 2014 Base Rate Subsequent Event Line of Credit	Jan. 09, 2014 Minimum LIBOR Revolving Credit Facility Subsequent Event Line of Credit	Jan. 09, 2014 Minimum LIBOR Term Loan Subsequent Event Line of Credit	Jan. 09, 2014 Minimum Base Rate Revolving Credit Facility Subsequent Event Line of Credit	Jan. 09, 2014 Minimum Base Rate Term Loan Subsequent Event Line of Credit	Jan. 09, 2014 Maximum LIBOR Revolving Credit Facility Subsequent Event Line of Credit	Jan. 09, 2014 Maximum LIBOR Term Loan Subsequent Event Line of Credit	Jan. 09, 2014 Maximum Base Rate Revolving Credit Facility Subsequent Event Line of Credit	Jan. 09, 2014 Maximum Base Rate Term Loan Subsequent Event Line of Credit	Jan. 09, 2014 Prior to December 31, 2015 Subsequent Event Line of Credit	Jan. 09, 2014 After December 31, 2015 Subsequent Event Line of Credit
Debt Instrument [Line Items]
Non-recourse mortgage loan			10 years
Original principal amount of non-recourse mortgage loan							$ 111,000,000.0
Maturity date of loan			Nov. 01, 2022
Interest rate			3.98%
Number of year non-recourse mortgage loan								7 years
Principal of non-recourse mortgage loan								21,900,000.0
Fixed rate interest on non-recourse loan								3.94%
Revolving credit facility borrowing limit, maximum borrowing capacity										250,000,000.0	400,000,000.0		350,000,000		250,000,000			100,000,000
Revolving credit facility borrowing limit, maximum allowable borrowing amount				222,300,000
Revolving credit facility outstanding amount				93,000,000													100,000,000	100,000,000
Interest rate on outstanding credit facility				1.80%
Interest expense				58,020,000	57,328,000	54,580,000						400,000
Years, maximum maturities of securities									30 years
Year, extension on term of revolving credit facility		1 year
Percent of secured indebtedness of the company's secured total asset value	55.00%
Line of credit facility material acquisition	greater than $100 million
Maximum leverage ratio of revolving credit facility	60.00%													60.00%
Minimum fixed charge coverage ratio on revolving credit facility	1.5																														1.5
Maximum secured leverage ratio on revolving credit facility	55.00%																													45.00%	40.00%
Percent minimum tangible net worth in relation to tangible net worth as of Offering										75.00%
Percent of net proceeds of any additional equity issuances in relation to net proceeds as of Offering										85.00%				75.00%
Maximum principal amount of recourse indebtedness outstanding at any time, aside from revolving credit facility	35,000,000.0
Percentage annual distributions cannot exceed funds from operations	95.00%													95.00%
Allowable additional borrowing capacity													250,000,000
Variable rate basis																				LIBOR	base rate
Basis spread on variable rate (in percents)																						1.35%	1.30%	0.35%	0.30%	1.95%	1.90%	0.95%	0.90%
Prime rate																					prime rate
Federal funds rate																					federal funds
Points added to federal funds rate (in percents)																					0.50%
Eurodollar																					Eurodollar
Points added to Eurodollar rate (in percents)																					100.00%
Extension term (in months)																6 months			12 months
Number of extensions available																2			3
Line of credit interest rate (in percents)																		3.08%
Maximum leverage ratio during a material acquisition period (in percents)														65.00%
Maximum secured leverage ratio during a material acquisition period (in percents)																														50.00%	45.00%
Minimum unsecured interest coverage ratio (in percents)																															175.00%
Maximum unsecured leverage ratio (in percents)														60.00%
Maximum unsecured leverage ratio during a material acquisition period (in percents)														65.00%
Minimum tangible net worth														$ 721,160,000.00
Maximum recourse indebtedness of total asset value (in percents)														15.00%