Pension and Severance Plans (Impact on Accumulated Other Comprehensive Income) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Tax Effect	$ 100,000	$ 100,000
Unrecognized pension costs	(10,510,000)	(4,710,000)	(6,980,000)
Amortization included in net periodic pension cost, net of tax	327,000	335,000
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Tax	100,000	200,000
Other Comprehensive Income (Loss), Minimum Pension Liability Net Adjustment, Tax	400,000	200,000
Net gain arising during period, net of tax	(6,127,000)	1,935,000
Adjustments to unrealized components of defined benefit pension plan included in other comprehensive income, net of tax	(5,800,000)	2,270,000
Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Tax	1,400,000	1,000,000
Estimated amortization of cost to be included in 2012 net periodic pension cost	556,000
Initial Net Obligation [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Unrecognized pension costs	(58,000)	(65,000)	(78,000)
Amortization included in net periodic pension cost, net of tax	7,000	13,000
Net gain arising during period, net of tax	0	0
Adjustments to unrealized components of defined benefit pension plan included in other comprehensive income, net of tax	7,000	13,000
Estimated amortization of cost to be included in 2012 net periodic pension cost	7,000
Prior Service Cost [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Unrecognized pension costs	(31,000)	(261,000)	(556,000)
Amortization included in net periodic pension cost, net of tax	255,000	295,000
Net gain arising during period, net of tax	(25,000)	0
Adjustments to unrealized components of defined benefit pension plan included in other comprehensive income, net of tax	230,000	295,000
Estimated amortization of cost to be included in 2012 net periodic pension cost	337,000
Actuarial Net Gain Loss [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Unrecognized pension costs	(10,421,000)	(4,384,000)	(6,346,000)
Amortization included in net periodic pension cost, net of tax	65,000	27,000
Net gain arising during period, net of tax	(6,102,000)	1,935,000
Adjustments to unrealized components of defined benefit pension plan included in other comprehensive income, net of tax	(6,037,000)	1,962,000
Estimated amortization of cost to be included in 2012 net periodic pension cost	$ 212,000