Senior Notes (Summary of Senior Notes) (Parenthetical) (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended
	Feb. 15, 2030	Oct. 27, 2017	Jul. 31, 2016	Dec. 31, 2023	Dec. 31, 2022	May 31, 2020	Oct. 31, 2017	Jul. 31, 2014
Debt Instrument [Line Items]
Long-term Debt				$ 1,115,629	$ 1,114,554
Senior notes 4.25% due 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.25%	4.25%
Long-term Debt								$ 300,000
Debt instrument, maturity date				Jul. 31, 2024
Redemption price, percentage of principal amount				100.00%
Additional issuance of long-term debt			$ 200,000
Senior notes 4.00% due 2030 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.00%	4.00%
Long-term Debt						$ 400,000
Debt instrument, maturity date				May 31, 2030
Senior notes 4.00% due 2030 [Member] | After February 15, 2030 [Member]
Debt Instrument [Line Items]
Redemption price, percentage of principal amount				100.00%
Senior notes 4.00% due 2030 [Member] | Measurement Input, Discount Rate [Member] | Prior to February 15, 2030 [Member]
Debt Instrument [Line Items]
Redemption at treasury rate basis point				0.50%
Senior notes 4.00% due 2030 [Member] | Forecast
Debt Instrument [Line Items]
Redemption price, percentage of principal amount	100.00%
Senior notes 5.20% due 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				5.20%	5.20%
Long-term Debt							$ 200,000
Debt instrument, maturity date				Oct. 31, 2047
Redemption price, percentage of principal amount				100.00%
Additional issuance of long-term debt		$ 25,000