Commitments and Contingencies Extended Warranty (Details) (USD $) In Thousands | 3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | Mar. 31, 2011 | Mar. 31, 2010 | |
| Beginning balanace | $ 14,637 | $ 5,870 | $ 19,109 | $ 9,665 | ||
| Unearned revenue for new extended warranties | 3,138 | 2,424 | 8,286 | 6,970 | ||
| Unearned revenue recognized | (283) | (389) | (959) | (1,140) | ||
| Ending balance | 21,964 | 11,700 | 21,964 | 11,700 | 19,109 | 9,665 |
| Extended Warranties Unearned Revenue Current | 1,162 | 1,147 | 1,162 | 1,147 | ||
| Long-term unearned revenue for extended warranty within Other long-term obligations | $ 20,802 | $ 10,553 | $ 20,802 | $ 10,553 | ||