Quarterly Financial Information (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Information (unaudited) [Abstract]
Revenues	$ 175,180	[1]	$ 166,559		$ 170,214		$ 165,218		$ 179,995	[2],[3]	$ 176,206		$ 169,596		$ 162,969		$ 677,170	$ 688,765	$ 720,333
Gross margin	28,217	[1]	30,619		32,061		16,300		37,503	[2],[3]	37,645		34,617		32,038
Income (loss) before income taxes	1,587	[1]	8,542		8,732		(4,116)		(176,688)	[2],[3]	16,745		10,268		7,368		14,746	(142,307)	77,775
Net income (loss)	604	[1]	5,028		5,057		(2,665)		(177,070)	[2],[3]	9,464		5,778		4,135		8,024	(157,693)	47,330
Basic earnings (loss) per share (in dollars per share)	$ 0.02	[1],[4]	$ 0.15	[4]	$ 0.15	[4]	$ (0.08)	[4]	$ (5.32)	[2],[3],[4]	$ 0.28	[4]	$ 0.17	[4]	$ 0.12	[4]
Diluted earnings (loss) per share (in dollars per share)	$ 0.02	[1],[4]	$ 0.15	[4]	$ 0.15	[4]	$ (0.08)	[4]	$ (5.32)	[2],[3],[4]	$ 0.28	[4]	$ 0.17	[4]	$ 0.12	[4]
Restructuring and related charges	1,773								9,000								1,773	9,036	10,258
Impairment loss									$ 183,300								$ 0	$ 183,288	$ 0

[1] Includes charges related to one-time termination benefits associated with capacity realignment of $1.8 million.

[2] Includes charges related to one-time termination benefits and costs associated with capacity reduction of $9.0 million and an impairment loss of $183.3 million primarily related to an impairment of goodwill.

[3] The assumed exercise of stock-based compensation awards for this period was not considered in the calculation of diluted earnings (loss) per share because the impact would have been anti-dilutive.

[4] We calculated earnings per share for each of the quarters based on the weighted average number of shares and dilutive options outstanding for each period. Accordingly, the sum of the quarters may not necessarily be equal to the full year income per share.