Notes Payable to Trusts - (Details)	1 Months Ended			12 Months Ended	60 Months Ended	61 Months Ended
	Jul. 31, 2005 USD ($) Security	May 31, 2005 USD ($) Security	Apr. 30, 2005 USD ($) Security	Dec. 31, 2016 USD ($)	Jun. 30, 2010	Jul. 31, 2010	Dec. 31, 2015 USD ($)
Variable Interest Entity [Line Items]
Unamortized deferred financing costs, net				$ 2,269,000			$ 2,399,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust III [Member]
Variable Interest Entity [Line Items]
Proceeds from issuance of securities	$ 41,238,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust III [Member] | Preferred Securities [Member]
Variable Interest Entity [Line Items]
Maturity date	Jul. 31, 2035
Issuance of securities	$ 40,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust III [Member] | Common Securities [Member]
Variable Interest Entity [Line Items]
Number of securities issued (in securities) | Security	1,238
Issuance of securities	$ 1,238,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust II [Member]
Variable Interest Entity [Line Items]
Proceeds from issuance of securities		$ 42,269,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust II [Member] | Preferred Securities [Member]
Variable Interest Entity [Line Items]
Maturity date		Jun. 30, 2035
Issuance of securities		$ 41,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust II [Member] | Common Securities [Member]
Variable Interest Entity [Line Items]
Number of securities issued (in securities) | Security		1,269
Issuance of securities		$ 1,269,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust I [Member]
Variable Interest Entity [Line Items]
Proceeds from issuance of securities			$ 36,083,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust I [Member] | Preferred Securities [Member]
Variable Interest Entity [Line Items]
Maturity date			Jun. 30, 2035
Issuance of securities			$ 35,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trust I [Member] | Common Securities [Member]
Variable Interest Entity [Line Items]
Number of securities issued (in securities) | Security			1,083
Issuance of securities			$ 1,083,000
Operating Partnership [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Trust III [Member]
Variable Interest Entity [Line Items]
Maturity date				Jul. 11, 2018
Interest rate, fixed (as a percent)						6.91%
Interest rate swap, fixed rate of interest				4.99%
Securities redemption date				Jul. 27, 2010
Operating Partnership [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Trust III [Member] | London Interbank Offered Rate (LIBOR) [Member]
Variable Interest Entity [Line Items]
Reference rate				three month LIBOR
Margin added to variable rate (as a percent)				2.40%
Operating Partnership [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Trust II [Member]
Variable Interest Entity [Line Items]
Maturity date				Jul. 11, 2018
Interest rate, fixed (as a percent)					6.67%
Interest rate swap, fixed rate of interest				4.99%
Securities redemption date				Jun. 30, 2010
Prepayment premium				$ 0
Operating Partnership [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Trust II [Member] | London Interbank Offered Rate (LIBOR) [Member]
Variable Interest Entity [Line Items]
Reference rate				three month LIBOR
Margin added to variable rate (as a percent)				2.40%
Operating Partnership [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Trust I [Member]
Variable Interest Entity [Line Items]
Maturity date				Jun. 30, 2018
Interest rate swap, fixed rate of interest				5.14%
Prepayment premium				$ 0
Operating Partnership [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Trust I [Member] | London Interbank Offered Rate (LIBOR) [Member]
Variable Interest Entity [Line Items]
Reference rate				three month LIBOR
Margin added to variable rate (as a percent)				2.30%