Reinsurance (Balance Sheet Reinsurance Results) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effects of Reinsurance [Line Items]
Reinsurance recoverables	$ 572,102	$ 563,428
Deferred policy acquisition costs	4,447,505	4,596,565	$ 4,344,361	$ 749,302
Deferred sales inducements	889,598	1,020,786	978,823	452,752
Value of business acquired	33,222	35,109	$ 30,287	$ 33,640
Other assets	85,310	121,086
Policyholders’ account balances	5,353,596	4,846,152
Future policy benefits	9,368,986	9,132,569
Reinsurance payables	232,937	262,588
Other liabilities	811,016	422,636
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	572,102	563,428
Deferred policy acquisition costs	3,703,166	3,766,066
Deferred sales inducements	476,608	540,389
Value of business acquired	(2,431)	(2,702)
Other assets	79,992	105,167
Policyholders’ account balances	3,098,537	2,825,030
Future policy benefits	5,680,939	5,511,496
Reinsurance payables	232,937	262,588
Other liabilities	290,330	329,019
Unaffiliated activity
Effects of Reinsurance [Line Items]
Reinsurance payables	$ 100	$ 100