Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity (Narrative) (Details)

v3.10.0.1
Shareholders' Equity (Narrative) (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Equity [Abstract]      
Stock repurchase plan, authorized amount $ 900,000,000    
Aggregate shares repurchased under stock repurchase plan 24,007,071    
Stock repurchased to date, value $ 763,663,000    
Stock Repurchased During Period, Value $ 201,599,847 $ 35,542,000 $ 11,000