|
Cash Equivalents and Investments - Schedule of Investments (Detail) (USD $)
In Thousands, unless otherwise specified |
Mar. 31, 2015
|
Dec. 31, 2014
|
|---|---|---|
| Schedule of Held-to-maturity Securities [Line Items] | ||
| Short-Term | $ 6,769 | $ 6,035 |
| Long-Term | 63,802 | 64,082 |
| Municipal Debt Securities [Member] | ||
| Schedule of Held-to-maturity Securities [Line Items] | ||
| Short-Term | 6,273 | 5,539 |
| Long-Term | 35,316 | 35,827 |
| Federal Home Loan Securities [Member] | ||
| Schedule of Held-to-maturity Securities [Line Items] | ||
| Long-Term | 27,261 | 27,030 |
| Certificates of Deposit [Member] | ||
| Schedule of Held-to-maturity Securities [Line Items] | ||
| Short-Term | 496 | 496 |
| Long-Term | $ 1,225 | $ 1,225 |