Long-Term Debt Shelf Arrangements (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Long-term Debt	$ (1,200,000)	$ (600,800)
Debt Instrument, Interest Rate, Stated Percentage	6.54%
Debt Instrument, Unused Borrowing Capacity, Amount	$ 255,000
Prudential [Member]
Line of Credit Facility [Line Items]
Long-term Debt	(300,000)
Debt Instrument, Unused Borrowing Capacity, Amount	105,000
MetLife [Member]
Line of Credit Facility [Line Items]
Long-term Debt	(50,000)
Debt Instrument, Unused Borrowing Capacity, Amount	150,000
Aggregate Shelf Agreements [Member]
Line of Credit Facility [Line Items]
Long-term Debt	(350,000)
Aggregated Unfunded Commitments [Member]
Line of Credit Facility [Line Items]
Long-term Debt	0
Aggregated Unfunded Commitments [Member] | Prudential [Member]
Line of Credit Facility [Line Items]
Long-term Debt	0
Aggregated Unfunded Commitments [Member] | MetLife [Member]
Line of Credit Facility [Line Items]
Long-term Debt	0
Uncollateralized Senior Note Due April Two Thousand Thirty Two [Member]
Line of Credit Facility [Line Items]
Long-term Debt	$ (59,500)	(66,500)
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Uncollateralized Senior Note Due August Two Thousand Thirty Nine [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.98%
Uncollateralized Senior Note Due July Two Thousand Thirty Five
Line of Credit Facility [Line Items]
Long-term Debt	$ (50,000)	(50,000)
Debt Instrument, Interest Rate, Stated Percentage	3.00%
Uncollateralized Senior Note Due August Two Thousand Thirty Five
Line of Credit Facility [Line Items]
Long-term Debt	$ (40,000)	$ (40,000)
Debt Instrument, Interest Rate, Stated Percentage	2.96%
Uncollateralized Senior Note Due March 14, 2038
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.43%
Uncollateralized Senior Note Due March 14, 2038 | Prudential [Member]
Line of Credit Facility [Line Items]
Long-term Debt	$ (80,000)
Maximum [Member] | Prudential [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount	405,000
Maximum [Member] | MetLife [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount	200,000
Maximum [Member] | Aggregate Shelf Agreements [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount	$ 605,000