Investment Operations Variable interest entities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Investment Holdings [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	$ 106,352	$ 103,701
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	162,978	151,341
LIHTC investments
Investment Holdings [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	42,907	54,037
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	43,834	55,597
Investment companies
Investment Holdings [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	53,388	40,236
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	103,125	79,578
Real estate limited partnerships
Investment Holdings [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	9,565	8,945
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	15,527	15,673
Other
Investment Holdings [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	492	483
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 492	$ 493