Organization and Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments
Initial minimum collateral as a percentage of fair value of domestic securities loaned	102.00%
Initial minimum collateral as a percentage of fair value of foreign securities loaned	105.00%
Cash
Book overdrafts, included in other liabilities	$ 137,000	$ 1,788,000
Property, Plant and Equipment, Gross [Abstract]
Capitalized internal use software development costs, net of accumulated amortization	93,646,000	66,012,000
Internal use software development costs capitalized	47,895,000	31,473,000	$ 14,640,000
Life insurance and annuity future benefits
Life insurance and annuity future benefits with life contingencies	15,955,510,000	15,349,322,000
Annuity contract benefits without life contingencies	11,104,721,000	10,569,147,000
Participating business
Participating life and annuity policy benefit liabilities	$ 6,890,616,000	$ 6,804,898,000
Participating business as a percentage of individual life insurance in-force	10.00%	9.00%
Participating business income as a percentage of individual life insurance premium income	20.00%	21.00%	32.00%
Minimum
Other intangible assets
Useful life of other intangible assets	2 years
Maximum
Other intangible assets
Useful life of other intangible assets	18 years
Life insurance and annuity future benefits
Life insurance and annuity future benefits with life contingencies	$ 4,500,000
Maximum | Internal use software
Property, Plant and Equipment, Gross [Abstract]
Useful life of internal use software	5 years
Weighted average
Other intangible assets
Useful life of other intangible assets	15 years