Investments (Other Invested Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Other Invested Assets [Line Items]
Other invested assets	$ 107,524	$ 89,536
LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	69,956	64,734
Company’s investment in separate accounts
Other Invested Assets [Line Items]
Other invested assets	3,320	3,418
Derivative instruments
Other Invested Assets [Line Items]
Other invested assets	34,248	21,384
Equity method | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	67,015	61,392
Equity method | Private equity | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	31,380	26,609
Equity method | Hedge funds | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	31,169	30,629
Equity method | Real estate-related | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	4,466	4,154
Fair Value | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	2,941	3,342
Fair Value | Private equity | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	567	774
Fair Value | Hedge funds | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	69	78
Fair Value | Real estate-related | LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	$ 2,305	$ 2,490