Common Stock and Treasury Stock (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Class A Common Stock
Common Stock [Line Items]
Balance, shares	6,370,000	6,360,000
Exercised options	7,000	10,000
Conversion of shares	1,000
Balance, shares	6,378,000	6,370,000
Class B Common Stock
Common Stock [Line Items]
Balance, shares	797,000	797,000
Exercised options	0	0
Conversion of shares	(1,000)
Balance, shares	796,000	797,000