Subsequent Events (Details Textual) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Proceeds From Issuance Of Common Stock			$ 35,042,235	$ 0	$ 31,072,752
Common Stock, Dividends, Per Share, Declared	$ 0.40	$ 0.40	$ 1.60	$ 1.60	$ 2.04
Subsequent Event [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Grants In Period			225,000
Proceeds From Issuance Of Common Stock			$ 44,900,000
Common Stock, Dividends, Per Share, Declared			$ 0.41
Plan 2005 [Member] | Subsequent Event [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Grants In Period			82,050
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Period			5 years
Stock Issued During Period, Shares, New Issues			1,725,000