Consolidated Balance Sheets (Parenthetical)	Mar. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	151,515,151	151,515,151
Common stock, shares outstanding	62,275,581	62,207,529