Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Calculation of basic and diluted earnings (loss) per share
Net income (loss) applicable to common shares	$ 8,244	$ (816)	$ 8,586	$ (1,772)
Tax-effected interest expense attributable to convertible notes	1,808
Net income (loss) assuming dilution	$ 10,052	$ (816)	$ 8,586	$ (1,772)
Weighted average common shares outstanding:
Basic shares	45,664	45,202	45,511	45,061
Effect of stock-based compensation	422		295
Effect of convertible notes	13,351
Diluted shares	59,437	45,202	45,806	45,061
Earnings (loss) per share:
Basic	$ 0.18	$ (0.02)	$ 0.19	$ (0.04)
Diluted	$ 0.17	$ (0.02)	$ 0.19	$ (0.04)