Derivative and Hedging Activities (Details) (USD $)	12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 2013 derivative [Domain]	Dec. 31, 2013 Fixed Rate Debt Hedged [Member]	Dec. 31, 2013 Fixed Rate Debt Hedged [Member] 2013 derivative [Domain]	Oct. 19, 2012 Medium-term Notes [Member]
Derivative [Line Items]
Forward starting interest rate swap date	Dec. 19, 2011		Apr. 02, 2013
Unsecured Debt	$ 150,000,000	$ 150,000,000			$ 125,000,000
Debt face amount						150,000,000
Notional amount			125,000,000.0	125,000,000
Derivative effective date	Jun. 07, 2013		Jun. 02, 2016
Fixed derivative rate			1.55%	1.26%
Credit spread	1.70%
All-in rate	2.96%		3.25%
Derivative lower range of basis spread	1.25%
Derivative higher range of basis spread	2.20%
Derivative net liability position	2,400,000
Interest payable derivative	87,000
Derivative other comprehensive amount to be reclassified into earnings	$ 1,300,000