XML 158 R138.htm IDEA: XBRL DOCUMENT v3.20.4
Valuation and Qualifying Accounts Valuation and Qualifying Accounts (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Employee severance accruals      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at beginning of year $ 837 $ 1,141 $ 0
Charged to costs and expenses 596 1,265 1,649
Deduction 1,271 1,569 508
Balance at  end of year 162 837 1,141
Valuation allowance of the deferred tax asset      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at beginning of year 233 276 244
Charged to costs and expenses 0 0 32
Deduction 11 43 0
Balance at  end of year 222 233 276
SEC Schedule, 12-09, Valuation Allowance, Current [Member]      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at beginning of year 849 769 835
Charged to costs and expenses 1,617 1,088 1,111
Deduction 1,179 1,008 1,177
Balance at  end of year 1,287 849 769
SEC Schedule, 12-09, Valuation Allowance, Noncurrent [Member]      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at beginning of year 1,290 1,227 2,278
Charged to costs and expenses 701 532 730
Deduction 347 469 1,781
Balance at  end of year $ 1,644 $ 1,290 $ 1,227