XML 72 R47.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Marketable Securities - Marketable securities portfolio (Details) - Debt securities (corporate and government) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Summary of marketable security portfolio    
Amortized Cost $ 284,795 $ 275,405
Net Unrealized Gains 75  
Net Unrealized Losses   (1,062)
Estimated Fair Value $ 284,870 $ 274,343
Minimum    
Summary of marketable security portfolio    
Contractual maturity dates 12 months  
Maximum    
Summary of marketable security portfolio    
Contractual maturity dates 18 months