Debt (Narrative) (Details) (USD $)	9 Months Ended				9 Months Ended		9 Months Ended						9 Months Ended			3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jun. 28, 2013	Dec. 31, 2012	Sep. 30, 2013 Debt Instrument, Name, Revolving Credit Facility [Member]	Jun. 28, 2013 Debt Instrument, Name, Revolving Credit Facility [Member]	Sep. 30, 2013 Debt Instrument, Name, 7 Year Term Loan [Member]	Jun. 28, 2013 Debt Instrument, Name, 7 Year Term Loan [Member]	Sep. 30, 2013 Debt Instrument, Name, Fannie Mae (A) [Member]	Jun. 28, 2013 Debt Instrument, Name, Fannie Mae (A) [Member]	Sep. 30, 2013 Debt Instrument, Name, Fannie Mae (B) [Member]	Jun. 28, 2013 Debt Instrument, Name, Fannie Mae (B) [Member]	Sep. 30, 2013 Debt Instrument, Name, Key Bank [Member]	Aug. 30, 2013 Debt Instrument, Name, Key Bank [Member]	May 01, 2012 Line of Credit Facility, 2012 Modification [Member]	Sep. 30, 2013 Interest Rate Swap, Maturity Date April 2019 [Member]	Sep. 30, 2013 Interest Rate Swap, Maturity Date June 2020 [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 370,000,000												$ 320,000,000
Long-term Debt									71,323,000		7,257,000
Debt Instrument, Interest Rate, Stated Percentage										6.85%		7.17%
Amortization	596,000	238,000
Write-off of debt issuance costs	353,000	0
Term Loans, Outstanding Balance								120,000,000
Debt Maturity, Years					5 years 0 months 0 days		7 years 0 months 0 days
Debt Maturity, Extension Option, Number Of Years					1 year 0 months 0 days
Credit Facility, Current Revolving Borrowing Capacity						250,000,000
Number of basis points over LIBOR	18				140		150						300
Unused balance of the unsecured revolving credit facility					59,000,000
Bank term loans - secured	0			19,250,000										19,250,000
Derivative, Fixed Interest Rate																3.04%	3.61%
Derivative, Description of Variable Rate Basis																1-month LIBOR	1-month LIBOR
Derivative, Basis Spread on Variable Rate																1.50%	1.50%
Derivative, Notional Amount																40,000,000	80,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value																189,000
Interest Rate Cash Flow Hedge Liability at Fair Value																	$ (708,000)