Schedule IV - Reinsurance (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Reinsurance [Abstract]      
Life insurance in force, gross amount [1] $ 10,178,956 $ 10,129,123 $ 9,739,048
Life insurance in force, net amount $ 10,178,956 $ 10,129,123 $ 9,739,048
Life insurance in force, percentage of amount assumed to net 0.00% 0.00% 0.00%
Premiums, gross amount [1] $ 2,945,017 $ 2,843,086 $ 2,199,351
Premiums, ceded to other companies 59,032 64,134 70,785
Premiums, assumed from other companies 4,656 4,202 0
Premiums, net amount $ 2,890,641 $ 2,783,154 $ 2,128,566
Premiums, percentage of amount assumed to net 0.20% 0.20% 0.00%
Reinsurance premiums for insurance companies intercompany elimination gross amount $ 3,457 $ 4,402 $ 4,354
Life Insurance [Member]      
Reinsurance [Abstract]      
Premiums, gross amount [1] 160,628 153,607 152,573
Premiums, ceded to other companies 8,838 9,596 10,328
Premiums, assumed from other companies 4,350 3,853 0
Premiums, net amount $ 156,140 $ 147,864 $ 142,245
Premiums, percentage of amount assumed to net 2.80% 2.60% 0.00%
Accident and Health Insurance [Member]      
Reinsurance [Abstract]      
Premiums, gross amount [1] $ 2,650,011 $ 2,552,699 $ 1,900,556
Premiums, ceded to other companies 3,148 4,778 5,765
Premiums, assumed from other companies 306 349 0
Premiums, net amount $ 2,647,169 $ 2,548,270 $ 1,894,791
Premiums, percentage of amount assumed to net 0.00% 0.00% 0.00%
Property and Casualty Insurance [Member]      
Reinsurance [Abstract]      
Premiums, gross amount [1] $ 134,378 $ 136,780 $ 146,222
Premiums, ceded to other companies 47,046 49,760 54,692
Premiums, assumed from other companies 0 0 0
Premiums, net amount $ 87,332 $ 87,020 $ 91,530
Premiums, percentage of amount assumed to net 0.00% 0.00% 0.00%
[1] Gross premiums amount is presented net of intercompany eliminations of $3,457, $4,402 and $4,354 for the years ended December 31, 2016, 2015, and 2014, respectively.