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Stock-Based Compensation Vested RSUs (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period 4 years    
Common stock, shares issued 52,580,246 51,818,186  
Restricted Stock Units (RSUs) | Common stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Allocated Share-based Compensation Expense $ 42,721    
Stock Incentive Plan | Common stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Shares Authorized 20,000,000.0    
Stock Incentive Plan | Restricted Stock Units (RSUs) | Common stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common stock, shares issued 16,700,000    
Allocated Share-based Compensation Expense $ 4,443 $ 4,216 $ 3,957
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Number of Shares [Roll Forward] [Roll Forward]      
Balance at Beginning of Period (shares) 45,000 42,000 34,000
Granted (shares) 22,000 15,000 16,000
Delivered (shares) (13,000) 12,000 8,000
Balance at End of Period (shares) 54,000 45,000 42,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Weighted Average Grant Date Fair Value [Abstract] [Abstract]      
Balance at beginning of period, Weighted Average Grant Date Fair Value (usd per share) $ 37.93 $ 36.98 $ 37.15
Granted, Weighted Average Grant Date Fair Value (usd per share) 50.29 38.29 38.14
Delivered, Weighted Average Grant Date Fair Value (usd per share) 37.61 34.95 40.03
Balance at end of period, Weighted Average Grant Date Fair Value (usd per share) $ 44.06 $ 37.93 $ 36.98
Stock Incentive Plan | Vested Restricted Stock Units (RSUs) | Common stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Allocated Share-based Compensation Expense $ 614 $ 626 $ 618