The Business and Summary of Significant Accounting Policies (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	$ 199,729	$ 106,114
Long-term investments	124,040	52,973
Fair value, measurements, recurring
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	19,795	126,086
Assets, fair value	343,564	285,173
Short-term investments, available-for-sale	199,729	106,114
Long-term investments	124,040	52,973
Fair value, measurements, recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	19,795	125,606
Assets, fair value	311,381	173,803
Short-term investments, available-for-sale	175,214	8,000
Long-term investments	116,372	40,197
Fair value, measurements, recurring | Significant Other Observable Inputs (Level 2)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	480
Assets, fair value	30,698	109,590
Short-term investments, available-for-sale	23,030	98,114
Long-term investments	7,668	10,996
Fair value, measurements, recurring | Significant Unobservable Inputs (Level 3)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Assets, fair value	1,485	1,781
Short-term investments, available-for-sale	1,485	0
Long-term investments	0	1,781
Fair value, measurements, recurring | Money market funds
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	19,795	125,606
Fair value, measurements, recurring | Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	19,795	125,606
Fair value, measurements, recurring | Money market funds | Significant Other Observable Inputs (Level 2)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Fair value, measurements, recurring | Money market funds | Significant Unobservable Inputs (Level 3)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Fair value, measurements, recurring | Certificates of deposit
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		480
Short-term investments, available-for-sale	23,030	16,981
Long-term investments	7,668	10,996
Fair value, measurements, recurring | Certificates of deposit | Quoted Prices in Active Markets for Identical Assets (Level 1)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		0
Short-term investments, available-for-sale	0	0
Long-term investments	0	0
Fair value, measurements, recurring | Certificates of deposit | Significant Other Observable Inputs (Level 2)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		480
Short-term investments, available-for-sale	23,030	16,981
Long-term investments	7,668	10,996
Fair value, measurements, recurring | Certificates of deposit | Significant Unobservable Inputs (Level 3)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		0
Short-term investments, available-for-sale	0	0
Long-term investments	0	0
Fair value, measurements, recurring | U.S. Treasury securities
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	175,214	8,000
Long-term investments	116,372	40,197
Fair value, measurements, recurring | U.S. Treasury securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	175,214	8,000
Long-term investments	116,372	40,197
Fair value, measurements, recurring | U.S. Treasury securities | Significant Other Observable Inputs (Level 2)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	0	0
Long-term investments	0	0
Fair value, measurements, recurring | U.S. Treasury securities | Significant Unobservable Inputs (Level 3)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	0	0
Long-term investments	0	0
Fair value, measurements, recurring | Preferred stock of U.S. corporation
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	1,485
Long-term investments		1,781
Fair value, measurements, recurring | Preferred stock of U.S. corporation | Quoted Prices in Active Markets for Identical Assets (Level 1)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	0
Long-term investments		0
Fair value, measurements, recurring | Preferred stock of U.S. corporation | Significant Other Observable Inputs (Level 2)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	0
Long-term investments		0
Fair value, measurements, recurring | Preferred stock of U.S. corporation | Significant Unobservable Inputs (Level 3)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale	$ 1,485
Long-term investments		1,781
Fair value, measurements, recurring | Corporate bonds
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		69,892
Fair value, measurements, recurring | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		0
Fair value, measurements, recurring | Corporate bonds | Significant Other Observable Inputs (Level 2)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		69,892
Fair value, measurements, recurring | Corporate bonds | Significant Unobservable Inputs (Level 3)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		0
Fair value, measurements, recurring | Commercial paper
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		11,240
Fair value, measurements, recurring | Commercial paper | Quoted Prices in Active Markets for Identical Assets (Level 1)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		0
Fair value, measurements, recurring | Commercial paper | Significant Other Observable Inputs (Level 2)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		11,240
Fair value, measurements, recurring | Commercial paper | Significant Unobservable Inputs (Level 3)
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Short-term investments, available-for-sale		$ 0