COMMON STOCK ACTIVITY (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at beginning of year (in shares)	26,973,531
Common stock offerings (in shares)	586,977	0	1,600,000
Stock options exercised (in shares)	9,250	18,000	57,436
Dividend reinvestment plan (in shares)	5,989	6,705	7,938
Shares outstanding at end of year (in shares)	27,658,059	26,973,531
Common Stocks Issuance Proceeds [Abstract]
Net proceeds from issuance of common stock through continuous equity program	$ 25,181,000	$ 303,000	$ 57,181,000
Proceeds from issuance of common stock common equity program	25,200,000		57,600,000
Common Stock Repurchase Plan [Abstract]
Treasury stock shares acquired	827,700
Common Stock [Member]
Common Stock Repurchase Plan [Abstract]
Common stocks outstanding authorized to be repurchased (in shares)	1,500,000
Total cost of shares repurchased	$ 14,170,000
Average cost per share of shares of common stock purchased (in dollar per share)	$ 17.1200
Number of Shares still authorized for repurchase (in shares)	672,300
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at beginning of year (in shares)	26,973,531	26,826,100	25,070,401
Common stock offerings (in shares)	586,977	0	1,600,000
Stock options exercised (in shares)	9,250	18,000	57,436
Dividend reinvestment plan (in shares)	5,989	6,705	7,938
Incentive restricted stock granted (in shares)	79,491	135,704	92,555
Incentive restricted stock forfeited (in shares)	(233)	0	(790)
Director common stock awarded (in shares)	6,618	6,690	7,074
Restricted stock withheld for tax obligations (in shares)	(3,564)	(19,668)	(8,514)
Shares outstanding at end of year (in shares)	27,658,059	26,973,531	26,826,100