Fair Values of Financial Instruments (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Financial Assets [Abstract]
Interest rate swap agreements	$ 2,021,000	$ 0
Carrying Amount [Member]
Financial Assets [Abstract]
Cash and cash equivalents	58,678,000	81,856,000
Mortgage Loan	3,502	0
Interest rate swap agreements	2,021	0
Financial Liabilities [Abstract]
Mortgage notes payable	1,097,493,000	605,889,000
Notes payable to banks	303,000,000	262,000,000
Interest rate swap agreements	8,429,000	16,285,000
Fair Value [Member]
Financial Assets [Abstract]
Cash and cash equivalents	58,678,000	81,856,000
Mortgage Loan	3,502	0
Interest rate swap agreements	2,021	0
Financial Liabilities [Abstract]
Mortgage notes payable	1,062,648,000	623,604,000
Notes payable to banks	302,393,000	254,215,000
Interest rate swap agreements	$ 8,429,000	$ 16,285,000