Long-Term Debt And Lines of Credit (Narrative) (Details) - USD ($) |
12 Months Ended | |||
---|---|---|---|---|
Jun. 20, 2018 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Aug. 02, 2019 |
|
Revolving Credit Facility [Member] | ||||
Debt Instrument [Line Items] | ||||
Borrowing amount | $ 450,000,000 | |||
2018 Credit Agreement [Member] | ||||
Debt Instrument [Line Items] | ||||
Standby letters of credit issued | $ 37,900,000 | |||
2018 Credit Agreement [Member] | LIBOR [Member] | ||||
Debt Instrument [Line Items] | ||||
Basis spread on variable interest rate | 1.00% | 1.00% | ||
2018 Credit Agreement [Member] | Revolving Credit Facility [Member] | ||||
Debt Instrument [Line Items] | ||||
Revolving credit facility period, years | 5 years | |||
Borrowing amount | $ 450,000,000 | |||
Deferred financing costs | $ 1,000,000.0 | |||
Unused lines of credit | $ 322,100,000 | |||
2018 Credit Agreement [Member] | Expansion Feature [Member] | ||||
Debt Instrument [Line Items] | ||||
Borrowing amount | $ 150,000,000 |