Shareholders' Equity (Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Mar. 31, 2009
Stock, shares authorized	200,000,000
Preferred stock, shares authorized	100,000,000
Common stock and stock units, shares issued and outstanding	23,173,226
Class A Common Stock
Stock, shares authorized	100,000,000	100,000,000
Common stock and stock units, shares issued and outstanding	21,979,000	21,967,000
Repurchase shares to satisfy tax withholdings obligations for incentive plan particiapants	6,959
Warrants issued to purchase common stock, shares			3,479,691
Exercise price			1.79
Warrants exercisable	Mar. 16, 2012
Warrants expiration	Mar. 16, 2019
Fair value of warrants			$ 940,000