v3.6.0.2

Investments - Components of Investments (Detail) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Cost Basis | $ 305,915 | $ 303,029
Unrealized Gains | 2 |
Unrealized Losses | (693) | (876)
Fair Value | 305,224 | 302,153
Investments [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost Basis | 303,521 | 300,735
Unrealized Gains | 2 |
Unrealized Losses | (693) | (876)
Fair Value | 302,830 | 299,859
Investments [Member] | Money Market Mutual Funds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost Basis | 18,118 | 18,181
Fair Value | 18,118 | 18,181
Investments [Member] | Commercial Paper [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost Basis | 27,906 | 5,986
Unrealized Losses | (39) | (5)
Fair Value | 27,867 | 5,981
Investments [Member] | US Government Agencies [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost Basis | 13,295 | 11,499
Unrealized Losses | (32) | (30)
Fair Value | 13,263 | 11,469
Investments [Member] | Corporate Bonds and Notes [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost Basis | 244,202 | 265,069
Unrealized Gains | 2 |
Unrealized Losses | (622) | (841)
Fair Value | 243,582 | 264,228
Deferred Compensation Plan Assets [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost Basis | 2,394 | 2,294
Fair Value | $ 2,394 | $ 2,294

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562 + Details
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 + Details
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