6. Debt Applicable Margin of Unsecured Credit Facility (Details) - Revolving Credit Facility [Member]	12 Months Ended
	Dec. 31, 2016
Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	60.00%
Pricing Level 1 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Pricing Level 2 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Pricing Level 2 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Pricing Level 3 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Pricing Level 3 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Pricing Level 4 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
Pricing Level 4 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Pricing Level 5 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
London Interbank Offered Rate (LIBOR) [Member] | Pricing Level 1 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.55%
London Interbank Offered Rate (LIBOR) [Member] | Pricing Level 2 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.65%
London Interbank Offered Rate (LIBOR) [Member] | Pricing Level 3 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.80%
London Interbank Offered Rate (LIBOR) [Member] | Pricing Level 4 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.95%
London Interbank Offered Rate (LIBOR) [Member] | Pricing Level 5 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.15%
Base Rate [Member] | Pricing Level 1 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.55%
Base Rate [Member] | Pricing Level 2 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.65%
Base Rate [Member] | Pricing Level 3 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.80%
Base Rate [Member] | Pricing Level 4 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.95%
Base Rate [Member] | Pricing Level 5 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.15%