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Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Valuation Allowance for Doubtful Accounts [Member] |  |  |
Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |
Balance at Beginning of Year | $ 5,243 | $ 4,135 | $ 3,909
Additions Acquisition Beginning Balance | 201 |  |
Additions Charged to Costs and Expenses | (728) | 1,435 | 825
Deductions & Write-offs | (2,933) | (327) | (599)
Balance at End of Year | 1,783 | 5,243 | 4,135
Valuation Allowance for Sales Returns [Member] |  |  |
Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |
Balance at Beginning of Year | 1,033 | 1,295 | 1,138
Additions Charged to Costs and Expenses | 200 | 124 | (142)
Deductions & Write-offs | 162 | (386) | 299
Balance at End of Year | 1,395 | 1,033 | 1,295
Valuation Allowance on Deferred Tax Asset [Member] |  |  |
Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |
Balance at Beginning of Year | 17,936 | 13,629 | 12,527
Additions Acquisition Beginning Balance | $ 5,876 |  |
Additions Charged to Costs and Expenses |  | 4,825 | 1,603
Deductions & Write-offs |  | (518) | (501)
Balance at End of Year |  | $ 17,936 | $ 13,629

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- Definition Amount of valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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- Definition Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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- Definition Amount of decrease in valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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