Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | |
| Statement of Income and Comprehensive Income [Abstract] | ||||
| Other comprehensive income (loss), tax | $ (283) | $ (120) | $ (154) | $ 836 |