Shareholders' Equity (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Sep. 30, 2011	Sep. 30, 2010	Mar. 31, 2011 ATM Program [Member]
Shareholders' Equity [Line Items]
Maximum offering price under ATM program			$ 100,000,000
Aggregate Number of Shares Sold	0	0			1,516,379
Aggregate Gross Proceeds					49,575,000
Aggregate Net Proceeds			$ 48,400,000	$ 0	$ 48,400,000
Average Sales Price Per Share					$ 32.69