Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investments:
Securities held to maturity, at amortized cost (fair value: $6,503,627 and $6,082,330)	$ 5,962,120	$ 5,641,909
Securities available for sale, at fair value (amortized cost: $2,568,512 and $2,422,650)	2,826,001	2,624,953
Mortgage loans, net of allowance for possible losses ($650 and $4,571)	142,170	157,460
Policy loans	71,549	74,967
Derivatives, index options	57,890	30,844
Other Long-term Investments	41,439	34,472
Total Investments	9,101,169	8,564,605
Cash and short-term investments	124,561	119,290
Deferred policy acquisition costs	705,397	722,542
Deferred sales inducements	152,844	155,753
Accrued investment income	92,665	87,875
Federal income tax receivable	5,655	0
Other assets	81,567	77,934
Total assets	10,263,858	9,727,999
Future policy benefits:
Universal life and annuity contracts	8,430,545	8,023,798
Traditional life and annuity contracts	138,309	139,657
Other policyholder liabilities	148,561	151,308
Deferred Federal income tax liability	55,054	46,481
Federal income tax payable	0	5,962
Other liabilities	99,709	84,008
Total liabilities	8,872,178	8,451,214
COMMITMENTS AND CONTINGENCIES (Notes 4, 7, and 9)
Common stock:
Additional paid-in capital	37,767	37,767
Accumulated other comprehensive income	76,786	53,176
Retained earnings	1,273,492	1,182,207
Total stockholders’ equity	1,391,680	1,276,785
Total liabilities and stockholders' equity	10,263,858	9,727,999
Common Class A [Member]
Common stock:
Common stock, value outstanding	3,435	3,435
Common Class B [Member]
Common stock:
Common stock, value outstanding	$ 200	$ 200