Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
Assets
Allowance for doubtful accounts	$ 242	$ 298
Liabilities:
Preferred stock, par value	$ 0.01	$ 0.01
Series B-1 Cumulative Convertible Redeemable Preferred Stock, shares issued	0	7,247,865
Series B-1 Cumulative Convertible Redeemable Preferred Stock, shares outstanding	0	7,247,865
Shareholders' equity of the Company:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	124,896,765	123,403,893
Common stock, shares outstanding	68,034,685	58,999,324
Treasury stock, shares	56,862,080	64,404,569
Series A Cumulative Preferred Stock
Shareholders' equity of the Company:
Preferred stock, shares issued	1,487,900	1,487,900
Preferred stock, shares outstanding	1,487,900	1,487,900
Series D Cumulative Preferred Stock
Shareholders' equity of the Company:
Preferred stock, shares issued	8,966,797	8,966,797
Preferred stock, shares outstanding	8,966,797	8,966,797
Series E Cumulative Preferred Stock
Shareholders' equity of the Company:
Preferred stock, shares issued	3,350,000	0
Preferred stock, shares outstanding	3,350,000	0