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Comprehensive Income and Accumulated Other Comprehensive Income - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 9 Months Ended
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Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract] |  |  |  |
Comprehensive income | $ 8,654 | $ 8,570 | $ 20,544 | $ 22,026
Comprehensive income tax rate |  |  | 35.00% |

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- Definition Amount Recognized In Accumulated Other Comprehensive Income Taxes Percentage + References No definition available. + Details
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- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Other Comprehensive Income -URI http://asc.fasb.org/extlink&oid=6519514 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Comprehensive Income -URI http://asc.fasb.org/extlink&oid=16317811 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e557-108580 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Net Income -URI http://asc.fasb.org/extlink&oid=6518256 + Details
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