Stockholders' Equity (Details) - USD ($)		3 Months Ended
	Jan. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Dividends Payable [Line Items]
Dividends declared and paid		$ 0	$ 0
NWLIC
Dividends Payable [Line Items]
Maximum dividend payment which may be paid without prior approval		152,800,000
Dividends declared and paid			32,000,000.0
Ozark National Life Insurance Company
Dividends Payable [Line Items]
Maximum dividend payment which may be paid without prior approval		17,200,000
Extraordinary dividend paid	$ 102,700,000
NIS
Dividends Payable [Line Items]
Dividends declared and paid		900,000
Class B
Dividends Payable [Line Items]
Dividends declared and paid		$ 0	$ 0
Class B | Board of Directors Chairman
Dividends Payable [Line Items]
Common stock, percentage ownership		99.00%