Consolidated Statements of Shareholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Balance, beginning of period at Dec. 31, 2008	$ 405,452	$ 284	$ 247,638	$ 149,469	$ 6,569	$ 1,492
Share outstanding, beginning of period at Dec. 31, 2008		28,398,000
Net income	61,156	0		61,011		145
Other comprehensive income (loss)
Foreign currency translation adjustments	3,475	0	0	0	3,427	48
Amortization of unrecognized losses	679	0	0	0	679	0
Decrease in pension liability, net of tax expense	2,429	0	0	0	2,429	0
Comprehensive income	67,739
Compensation expense recognized for employee stock options	3,279	0	3,279	0	0	0
Exercise of options		84,000
Exercise of options	746	1	745	0	0	0
Tax benefit of non-qualifying stock options	30	0	30	0	0	0
Other	0	0	0	0	0	0
Proceeds from issuance of warrants	0
Balance, end of period at Dec. 31, 2009	477,246	285	251,692	210,480	13,104	1,685
Share outstanding, end of period at Dec. 31, 2009		28,482,000
Net income	20,505	0		20,160		345
Other comprehensive income (loss)
Foreign currency translation adjustments	(2,573)	0	0	0	(2,753)	180
Amortization of unrecognized losses	270	0	0	0	270	0
Decrease in pension liability, net of tax expense	(810)	0	0	0	(810)	0
Comprehensive income	17,392
Compensation expense recognized for employee stock options	4,933	0	4,933	0	0	0
Exercise of options		350,000
Exercise of options	1,063	1	1,062	0	0	0
Tax benefit of non-qualifying stock options	796	0	796	0	0	0
Other	(56)	2	(58)	0	0	0
Proceeds from issuance of warrants	0
Balance, end of period at Dec. 31, 2010	501,374	288	258,425	230,640	9,811	2,210
Share outstanding, end of period at Dec. 31, 2010	28,831,724	28,832,000
Net income	44,244	0	0	44,076	0	168
Other comprehensive income (loss)
Foreign currency translation adjustments	(2,169)	0	0	0	(2,303)	134
Amortization of unrecognized losses	365	0	0	0	365	0
Decrease in pension liability, net of tax expense	(4,880)	0	0	0	(4,880)	0
Comprehensive income	37,560
Compensation expense recognized for employee stock options	5,433	0	5,433	0	0	0
Exercise of options		781,000
Exercise of options	7,027	8	7,019	0	0	0
Tax benefit of non-qualifying stock options	7,879	0	7,879	0	0	0
Other	(1,098)	0	(1,098)	0	0	0
Equity component of convertible notes issuance, net of deferred financing fees and deferred taxes	48,521	0	48,521	0	0	0
Proceeds from issuance of warrants	48,848	0	48,848	0	0	0
Purchase of call options net of deferred taxes	(41,993)	0	(41,993)	0	0	0
Balance, end of period at Dec. 31, 2011	$ 613,551	$ 296	$ 333,034	$ 274,716	$ 2,993	$ 2,512
Share outstanding, end of period at Dec. 31, 2011	29,612,684	29,613,000