Fair Value Measurements (Assets Measured At Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	$ 27,968	$ 36,816
Fixed income mutual fund
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	2,492	2,492
U.S. government and agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	1,313	951
Corporate obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	12,018	22,145
Other fixed income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	871	491
International securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	11,274	10,311
Municipal obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments		426
Quoted Market Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	2,492	2,492
Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Fixed income mutual fund
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	2,492	2,492
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	25,476	34,324
Significant Other Observable Inputs (Level 2) | U.S. government and agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	1,313	951
Significant Other Observable Inputs (Level 2) | Corporate obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	12,018	22,145
Significant Other Observable Inputs (Level 2) | Other fixed income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	871	491
Significant Other Observable Inputs (Level 2) | International securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments	11,274	10,311
Significant Other Observable Inputs (Level 2) | Municipal obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Short-term investments		$ 426