Related Party Transactions (Narrative) (Details) - USD ($)	3 Months Ended					12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019
Related Party Transaction [Line Items]
Investment expense	$ 6,393,000	$ 3,953,000
Commissions and fees	496,869,000	507,934,000
Other invested assets	505,569,000					$ 474,013,000
Net investment income	123,037,000	125,069,000
Fee income from revenue sharing agreement	145,133,000	109,388,000
Contributed capital	0					0
Prudential Insurance
Related Party Transaction [Line Items]
Stock option program plan expense	0.0	0
Deferred compensation program expense	200,000	300,000
Pension plan expense	700,000	500,000
Welfare plan expense	$ 600,000	500,000
Defined contribution plan employer matching contribution percent	4.00%
Defined contribution plan, cost recognized	$ 300,000	200,000
Affiliated Entity
Related Party Transaction [Line Items]
Accrued interest receivable related to long-term notes receivables	100,000					0.0
Revenue related to long-term notes receivable	400,000	200,000
Interest expense related to loans payable	28,000,000	16,000,000
Affiliated Entity | PAD
Related Party Transaction [Line Items]
Commissions and fees	23,000,000	24,000,000
Affiliated Entity | ASTISI and PGIM Investments
Related Party Transaction [Line Items]
Fee income from revenue sharing agreement	23,000,000	24,000,000
Affiliated Entity | PGIM
Related Party Transaction [Line Items]
Investment expense	5,000,000	3,000,000
Prudential Financial Joint Venture
Related Party Transaction [Line Items]
Other invested assets	403,000,000					$ 391,000,000
Net investment income	18,000,000	5,000,000
Prudential Financial
Related Party Transaction [Line Items]
Company's share of corporate expenses (benefits)	5,000,000	4,000,000
Line of credit facility, maximum borrowing capacity	9,000,000,000
PAI
Related Party Transaction [Line Items]
Return of capital	$ 207,000,000	$ 245,000,000	$ 241,000,000	$ 247,000,000	$ 245,000,000