Dividends From Subsidiaries And Statutory Financial Information (Schedule of Combined Net Income and Policyholders' Surplus in Accordance with Statutory Accounting Practices) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Insurance [Abstract]
Amount available for dividend distribution without prior approval from regulatory authorities	$ 1,100,000
Net income	1,099,953	$ 698,862	$ 702,830
Policyholders' surplus	5,587,930	$ 5,479,603	$ 5,493,044
Increase in BIC's statutory capital and surplus	$ 282,000
Total Adjusted Capital percentage threshold	200.00%
BIC's Total Adjusted Capital balance	$ 5,306,000
BIC's Total Adjusted Capital balance as percentage of RBC Authorized Control Level	384.00%