Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Common stock, shares issued under employee stock purchase plan (shares)	20	50
Common stock, proceeds from issuance of shares in connection with dividend reinvestment and stock purchase plan (shares)	3,100	178,006