|
Cash, Cash Equivalents, and Short-Term Investments (Details) (USD $)
In Thousands, unless otherwise specified
|
Mar. 31, 2015
|
Dec. 31, 2014
|
Mar. 31, 2014
|
Dec. 31, 2013
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Cash and cash equivalents, at cost |
$ 257,236 |
$ 368,531 |
$ 308,448 |
$ 297,818 |
| Cash, Available-for-sale Securities and Other Short-term Investments, Cost Basis |
498,521 |
721,869 |
|
|
| Available-for-sale Securities, Gross Unrealized Gain |
290 |
225 |
|
|
| Available-for-sale Securities, Gross Unrealized Losses |
(97) |
(433) |
|
|
| Cash and Cash Equivalents, Fair Value Disclosure |
257,236 |
368,531 |
|
|
| Total Short-term Investments, Fair Value Disclosure |
241,478 |
353,130 |
|
|
| Total Cash, Cash Equivalents, and Short-term Investments, Estimated Fair Value |
498,714 |
721,661 |
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |
|
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value |
50,962 |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses |
(94) |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value |
1,026 |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses Accumulated in Investments |
(3) |
|
|
|
| Total |
241,285 |
353,338 |
|
|
| Corporate Notes and Bonds [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Available-for-sale Securities, Amortized Cost Basis |
114,165 |
196,401 |
|
|
| Available-for-sale Securities, Gross Unrealized Gain |
157 |
84 |
|
|
| Available-for-sale Securities, Gross Unrealized Losses |
(86) |
(371) |
|
|
| Available-for-sale Securities, Estimated Fair Value |
114,236 |
196,114 |
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |
|
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value |
32,411 |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses |
(83) |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value |
1,026 |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses Accumulated in Investments |
(3) |
|
|
|
| US Government Agencies Debt Securities [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Available-for-sale Securities, Amortized Cost Basis |
29,072 |
51,987 |
|
|
| Available-for-sale Securities, Gross Unrealized Gain |
35 |
13 |
|
|
| Available-for-sale Securities, Gross Unrealized Losses |
(6) |
(44) |
|
|
| Available-for-sale Securities, Estimated Fair Value |
29,101 |
51,956 |
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |
|
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value |
12,009 |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses |
(6) |
|
|
|
| Certificates of Deposit [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Available-for-sale Securities, Amortized Cost Basis |
1,920 |
1,920 |
|
|
| Available-for-sale Securities, Gross Unrealized Gain |
0 |
0 |
|
|
| Available-for-sale Securities, Gross Unrealized Losses |
0 |
0 |
|
|
| Available-for-sale Securities, Estimated Fair Value |
1,920 |
1,920 |
|
|
| Commercial Paper, Not Included with Cash and Cash Equivalents [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Available-for-sale Securities, Amortized Cost Basis |
8,992 |
1,996 |
|
|
| Available-for-sale Securities, Gross Unrealized Gain |
0 |
0 |
|
|
| Available-for-sale Securities, Gross Unrealized Losses |
0 |
0 |
|
|
| Available-for-sale Securities, Estimated Fair Value |
8,992 |
1,996 |
|
|
| Time Deposits [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Other Short-term Investments, Cost Basis |
21,773 |
26,395 |
|
|
| Available-for-sale Securities, Gross Unrealized Gain |
0 |
0 |
|
|
| Available-for-sale Securities, Gross Unrealized Losses |
0 |
0 |
|
|
| Other Short-term Investments, Estimated Fair Value |
21,773 |
26,395 |
|
|
| Municipal Notes and Bonds [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Available-for-sale Securities, Amortized Cost Basis |
65,363 |
74,639 |
|
|
| Available-for-sale Securities, Gross Unrealized Gain |
98 |
128 |
|
|
| Available-for-sale Securities, Gross Unrealized Losses |
(5) |
(18) |
|
|
| Available-for-sale Securities, Estimated Fair Value |
65,456 |
74,749 |
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |
|
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value |
6,542 |
|
|
|
| Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses |
(5) |
|
|
|
| Commercial Paper [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Cash and cash equivalents, at cost |
4,000 |
|
|
|
| Cash and Cash Equivalents, Fair Value Disclosure |
4,000 |
|
|
|
| Cash [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Cash and cash equivalents, at cost |
251,867 |
353,187 |
|
|
| Cash and Cash Equivalents, Fair Value Disclosure |
251,867 |
353,187 |
|
|
| Money Market Funds [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Cash and cash equivalents, at cost |
1,369 |
15,344 |
|
|
| Cash and Cash Equivalents, Fair Value Disclosure |
1,369 |
15,344 |
|
|
| Cash Equivalents [Member] |
|
|
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
|
|
| Cash and cash equivalents, at cost |
5,369 |
15,344 |
|
|
| Cash and Cash Equivalents, Fair Value Disclosure |
$ 5,369 |
$ 15,344 |
|
|