MARKETABLE SECURITIES (Details) (USD $) | 9 Months Ended |
In Thousands, unless otherwise specified | Sep. 30, 2013 |
Short-term Marketable Securities | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | $111,226 |
Marketable Securities, Gross Unrealized Gains | 33 |
Marketable Securities, Gross Unrealized Losses | -20 |
Marketable Securities, Fair Value | 111,239 |
Short-term Marketable Securities | Municipal Bonds | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | 71,854 |
Marketable Securities, Gross Unrealized Gains | 21 |
Marketable Securities, Gross Unrealized Losses | -20 |
Marketable Securities, Fair Value | 71,855 |
Short-term Marketable Securities | Municipal Bonds | Maximum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '1 year |
Short-term Marketable Securities | Corporate Debt Securities | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | 16,440 |
Marketable Securities, Gross Unrealized Gains | 7 |
Marketable Securities, Gross Unrealized Losses | 0 |
Marketable Securities, Fair Value | 16,447 |
Short-term Marketable Securities | Corporate Debt Securities | Maximum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '1 year |
Short-term Marketable Securities | Commercial Paper | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | 22,932 |
Marketable Securities, Gross Unrealized Gains | 5 |
Marketable Securities, Gross Unrealized Losses | 0 |
Marketable Securities, Fair Value | 22,937 |
Short-term Marketable Securities | Commercial Paper | Maximum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '1 year |
Long-term Marketable Securities | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | 50,644 |
Marketable Securities, Gross Unrealized Gains | 22 |
Marketable Securities, Gross Unrealized Losses | -13 |
Marketable Securities, Fair Value | 50,653 |
Long-term Marketable Securities | Municipal Bonds | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | 19,771 |
Marketable Securities, Gross Unrealized Gains | 11 |
Marketable Securities, Gross Unrealized Losses | -10 |
Marketable Securities, Fair Value | 19,772 |
Long-term Marketable Securities | Municipal Bonds | Minimum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '1 year |
Long-term Marketable Securities | Municipal Bonds | Maximum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '2 years |
Long-term Marketable Securities | Corporate Debt Securities | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | 23,380 |
Marketable Securities, Gross Unrealized Gains | 11 |
Marketable Securities, Gross Unrealized Losses | -2 |
Marketable Securities, Fair Value | 23,389 |
Long-term Marketable Securities | Corporate Debt Securities | Minimum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '1 year |
Long-term Marketable Securities | Corporate Debt Securities | Maximum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '2 years |
Long-term Marketable Securities | Asset-backed Securities | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Amortized Cost Basis | 7,493 |
Marketable Securities, Gross Unrealized Gains | 0 |
Marketable Securities, Gross Unrealized Losses | -1 |
Marketable Securities, Fair Value | $7,492 |
Long-term Marketable Securities | Asset-backed Securities | Minimum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '1 year |
Long-term Marketable Securities | Asset-backed Securities | Maximum | ' |
Schedule of Marketable Securities | ' |
Marketable Securities, Contractual Maturity | '2 years |