Fair Value Measurements (Summary Of Fair Value Of Financial Assets And Liabilities Measured At Recurring Basis And Valuation Techniques) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	$ 62,360		$ 61,606
Total assets	169,323		131,596
Total liabilities	2,991		4,082
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	117,277		72,855
Total liabilities
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	52,046		58,741
Total liabilities	236		300
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets
Total liabilities	2,755		3,782
Income Approach Valuation Techniques [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	2,755		3,782
Income Approach Valuation Techniques [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration
Income Approach Valuation Techniques [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration
Income Approach Valuation Techniques [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	2,755		3,782
Market Approach Valuation Techniques [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	104,249		65,811
Market Approach Valuation Techniques [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	9,496		6,921
Market Approach Valuation Techniques [Member] | U.S. Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	3,532		5,551
Market Approach Valuation Techniques [Member] | Corporate Notes/Bonds[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	47,612		47,528
Market Approach Valuation Techniques [Member] | Certificates/Term Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	3,042		2,922
Market Approach Valuation Techniques [Member] | Derivative Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,392	[1]	2,863	[1]
Market Approach Valuation Techniques [Member] | Derivative Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	236	[1]	300	[1]
Market Approach Valuation Techniques [Member] | Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	104,249		65,811
Market Approach Valuation Techniques [Member] | Level 1 [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	9,496		3,499
Market Approach Valuation Techniques [Member] | Level 1 [Member] | U.S. Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	3,532		3,545
Market Approach Valuation Techniques [Member] | Level 1 [Member] | Corporate Notes/Bonds[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 1 [Member] | Certificates/Term Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 1 [Member] | Derivative Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		[1]		[1]
Market Approach Valuation Techniques [Member] | Level 1 [Member] | Derivative Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		[1]		[1]
Market Approach Valuation Techniques [Member] | Level 2 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 2 [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total			3,422
Market Approach Valuation Techniques [Member] | Level 2 [Member] | U.S. Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total			2,006
Market Approach Valuation Techniques [Member] | Level 2 [Member] | Corporate Notes/Bonds[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	47,612		47,528
Market Approach Valuation Techniques [Member] | Level 2 [Member] | Certificates/Term Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total	3,042		2,922
Market Approach Valuation Techniques [Member] | Level 2 [Member] | Derivative Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,392	[1]	2,863	[1]
Market Approach Valuation Techniques [Member] | Level 2 [Member] | Derivative Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	236	[1]	300	[1]
Market Approach Valuation Techniques [Member] | Level 3 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 3 [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 3 [Member] | U.S. Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 3 [Member] | Corporate Notes/Bonds[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 3 [Member] | Certificates/Term Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Total
Market Approach Valuation Techniques [Member] | Level 3 [Member] | Derivative Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		[1]		[1]
Market Approach Valuation Techniques [Member] | Level 3 [Member] | Derivative Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		[1]		[1]

[1] See Note 15 - Derivative Instruments for details.