XML 36 R25.htm IDEA: XBRL DOCUMENT v3.21.1
FAIR VALUE MEASUREMENTS (Tables)
3 Months Ended
Mar. 31, 2021
Fair Value Measurements  
Valuation of marketable securities

March 31, 2021

Quoted Priced in Active Markets

Significant Other

Significant

for Identical Instruments

Observable Inputs

Unobservable Inputs

    

(Level 1)

    

(Level 2)

    

(Level 3)

    

Total

Marketable securities

$

46,876

$

$

$

46,876

December 31, 2020

Quoted Prices in Active Markets

Significant Other

Significant

for Identical Instruments

Observable Inputs

Unobservable Inputs

    

(Level 1)

    

(Level 2)

    

(Level 3)

    

Total

Marketable securities

$

40,411

$

$

$

40,411

Valuation of senior notes

March 31, 2021

December 31, 2020

Carrying Amount

Estimated Fair Value

Carrying Amount

Estimated Fair Value

Senior Notes

$

4,124,168

$

4,402,833

$

4,123,217

$

4,647,595