Summary Of Significant Accounting Policies (Narrative) (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting Policies [Line Items]
Cash equivalents	$ 247,000,000	$ 286,100,000
Long-term investments	11,400,000
Unrealized losses still held	1,433,000	1,851,000
Fair value of auction rate securities	9,900,000
Unrealized gains on long-term Investments	400,000	1,500,000	500,000
Options to purchase of common shares	1.2	3.7	3.4
Compensation cost recognized for stock-based awards	7,100,000	6,300,000	5,100,000
Income tax benefit recognized in the income statement for stock-based awards	2,600,000	2,100,000	1,700,000
Stock options issued	0.3	0.4	0.4
Total cash received as a result of stock option exercises	11,203,000	4,657,000	2,571,000
Tax benefit realized as a result of stock option exercises and the vesting of other share-based awards	2,200,000	1,300,000	900,000
Total intrinsic value of stock options exercised	3,200,000	1,400,000	1,400,000
Expenses related to foreign currency translation	900,000	1,200,000	1,500,000
Stock Options [Member]
Summary Of Significant Accounting Policies [Line Items]
Total unrecognized compensation cost	3,839,000
Remaining weighted-average amortization period	2 years 2 months 12 days
Weighted-average fair value per option granted	$ 7.87	$ 6.83	$ 8.14
Restricted Shares [Member]
Summary Of Significant Accounting Policies [Line Items]
Total unrecognized compensation cost	2,166,000
Remaining weighted-average amortization period	1 year 9 months 18 days
Restricted Stock Units And Phantom Stock Awards [Member]
Summary Of Significant Accounting Policies [Line Items]
Total unrecognized compensation cost	4,081,000
Remaining weighted-average amortization period	2 years 9 months 18 days
Performance Based Restricted Stock Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Total unrecognized compensation cost	$ 1,565,000
Remaining weighted-average amortization period	2 years 2 months 12 days
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate reset period	7 days
Maturity term	10 years
Minimum [Member] | Buildings And Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	5 years
Minimum [Member] | Machinery And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	2 years
Minimum [Member] | Furniture And Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	2 years
Minimum [Member] | Vehicles [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	2 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate reset period	35 days
Maximum [Member] | Buildings And Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	40 years
Maximum [Member] | Machinery And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	10 years
Maximum [Member] | Furniture And Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	10 years
Maximum [Member] | Vehicles [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	5 years