Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued
Common Class A [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	40,000,000	30,000,000
Common stock, shares issued	21,360,992	20,941,821
Common stock, shares outstanding	20,440,130	20,025,199
Common Class B [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	5,649,240	5,649,240
Common stock, shares outstanding	5,576,775	5,576,775