Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Details)

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Income Taxes - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Jan. 01, 2019
Jan. 01, 2018
Jan. 01, 2017
Dec. 31, 2016
Income Tax Contingency [Line Items]              
Investment tax credit $ 18,800,000 $ 14,900,000          
Deferred tax asset, valuation allowance 12,120,000 10,506,000          
Valuation allowance, deferred tax asset, increase (decrease) 1,600,000            
Deferred tax assets, gross 450,294,000 352,038,000          
Cumulative effect of adoption       $ 0 $ 1,992,000 $ 2,996,000  
Deferred tax assets, operating loss carryforwards, domestic             $ 8,600,000
Deferred tax assets, operating loss carryforwards, state and local             6,800,000
Retained earnings 251,466,000 229,391,000          
Unrecognized tax benefits 0 647,000 $ 1,525,000       1,525,000
Unrecognized tax benefits, interest and penalties 0.0 200,000          
Income tax benefit, expiration of statute of limitations 647,000 878,000 $ 0        
Retained Earnings (Accumulated Deficit)              
Income Tax Contingency [Line Items]              
Cumulative effect of adoption       $ 740,000   2,996,000  
U.S. Federal              
Income Tax Contingency [Line Items]              
Net operating loss carryforwards 718,100,000            
U.S. Federal and State              
Income Tax Contingency [Line Items]              
Income tax benefit, expiration of statute of limitations 800,000            
State              
Income Tax Contingency [Line Items]              
Net operating loss carryforwards 1,300,000,000            
California Enterprise Zone Credits.              
Income Tax Contingency [Line Items]              
Investment tax credit $ 1,000,000.0 1,000,000.0          
Accounting Standards Update 2016-16 | Adjustment              
Income Tax Contingency [Line Items]              
Prepaid taxes           (378,500,000)  
Deferred tax assets, gross           378,200,000  
Cumulative effect of adoption           (300,000)  
Accounting Standards Update 2016-09 | Deferred Tax Asset              
Income Tax Contingency [Line Items]              
Cumulative effect of adoption           (3,300,000)  
Accounting Standards Update 2016-09 | Retained Earnings (Accumulated Deficit)              
Income Tax Contingency [Line Items]              
Cumulative effect of adoption           $ 3,300,000  
Retained earnings             $ 3,300,000
Indefinite [Member] | U.S. Federal              
Income Tax Contingency [Line Items]              
Net operating loss carryforwards   535,100,000          
Indefinite [Member] | State              
Income Tax Contingency [Line Items]              
Net operating loss carryforwards   $ 102,400,000