Reinsurance (Reinsurance Recoverable by Counterparty) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 4,310,574	$ 3,200,642
Prudential Insurance
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,265,669	1,245,450
PAR U
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,073,143	1,027,304
PARCC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	461,524	458,441
PAR Term
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	232,857	219,757
Term Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	212,540	190,633
DART
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	49,662	38,651
Pruco Life
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	14,196	16,428
Unaffiliated
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 983	$ 3,978