Federal Income Taxes (Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Future policy benefits, excess of financial accounting liabilities over tax liabilities	$ 278,407	$ 271,637
Investment securities write-downs for financial accounting purposes	6,724	8,684
Pension liabilities	8,461	7,841
Accrued operating expenses recorded for financial accounting purposes not currently tax deductible	7,380	6,535
Mortgage loans, principally due to valuation allowances for financial accounting purposes	228	1,600
Accrued and unearned investment income recognized for tax purposes and deferred for financial accounting purposes	156	265
Capital loss carryforward	0	0
Other	(4,690)	(850)
Total gross deferred tax assets	296,666	295,712
Deferred tax liabilities:
Deferred policy acquisition and sales inducement costs, principally expensed for tax purposes	(298,435)	(296,797)
Debt securities, principally due to deferred market discount for tax	(8,680)	(8,091)
Real estate, principally due to adjustments for financial accounting purposes	(117)	(272)
Net unrealized gains on securities available for sale	(45,927)	(37,025)
Foreign currency translation adjustments	4,118	3,276
Fixed assets, due to different bases	(2,342)	(3,249)
Other	(337)	(35)
Total gross deferred tax liabilities	(351,720)	(342,193)
Net deferred tax liabilities	$ (55,054)	$ (46,481)