States whether the entity was in compliance with the debt covenants throughout the reporting period, and describes facts and circumstances of any compliance failure.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Weighted average interest rate of debt outstanding.

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Amount of borrowings from a bank classified as other, maturing within one year or operating cycle, if longer.

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DEBT (Long-Term Debt) (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
DEBT (Long-Term Debt) (Details) - USD ($) $ in Thousands	Oct. 31, 2016	Apr. 30, 2015	Dec. 31, 2020	Dec. 31, 2019	Oct. 20, 2016	Apr. 01, 2015
Debt Instrument [Line Items]
Amounts due banks			$ 2,623	$ 34,857
Fair value of long-term debt			$ 793,591	$ 721,494
Senior Notes 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 350,000
Debt Instrument, Issuance Date	Oct. 20, 2016
Senior Notes [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate			3.30%
Debt Instrument, Covenant Compliance			As of December 31, 2020, the Company was in compliance with all of its debt covenants.
Weighted Average [Member]
Debt Instrument [Line Items]
Debt Instrument, Term			13 years 4 months 24 days
Senior Notes 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount						$ 350,000
Debt Instrument, Issuance Date		Apr. 01, 2015
Minimum \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.80%
Maximum \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.00%
Senior Notes Series A [Member] \| Senior Notes 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 100,000
Debt Instrument, Maturity Date			Oct. 20, 2028
Debt Instrument, Interest Rate, Stated Percentage			2.75%
Senior Notes Series A [Member] \| Senior Notes 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 100,000
Debt Instrument, Maturity Date			Aug. 20, 2025
Debt Instrument, Interest Rate, Stated Percentage			3.15%
Senior Notes Series B [Member] \| Senior Notes 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 100,000
Debt Instrument, Maturity Date			Oct. 20, 2033
Debt Instrument, Interest Rate, Stated Percentage			3.03%
Senior Notes Series B [Member] \| Senior Notes 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 100,000
Debt Instrument, Maturity Date			Aug. 20, 2030
Debt Instrument, Interest Rate, Stated Percentage			3.35%
Senior Notes Series C [Member] \| Senior Notes 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 100,000
Debt Instrument, Maturity Date			Oct. 20, 2037
Debt Instrument, Interest Rate, Stated Percentage			3.27%
Senior Notes Series C [Member] \| Senior Notes 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 50,000
Debt Instrument, Maturity Date			Apr. 01, 2035
Debt Instrument, Interest Rate, Stated Percentage			3.61%
Senior Notes Series D [Member] \| Senior Notes 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 50,000
Debt Instrument, Maturity Date			Oct. 20, 2041
Debt Instrument, Interest Rate, Stated Percentage			3.52%
Senior Notes Series D [Member] \| Senior Notes 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 100,000
Debt Instrument, Maturity Date			Apr. 01, 2045
Debt Instrument, Interest Rate, Stated Percentage			4.02%