Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net earnings	$ 16,632	$ 19,741
Adjustments to reconcile net earnings to net cash from operating activities:
Universal life and annuity contract interest	140,300	101,543
Surrender charges and other policy revenues	(3,605)	(3,500)
Realized (gains) losses on investments	(2,313)	(1,167)
Accrual and amortization of investment income	(447)	(708)
Depreciation and amortization	1,406	1,417
(Increase) decrease in value of index options	(74,432)	(42,355)
(Increase) decrease in deferred policy acquisition and sales inducement costs	(453)	2,427
(Increase) decrease in other assets	(4,933)	(4,200)
(Increase) decrease in other assets	(500)	(4,734)
Increase (decrease) in liabilities for future policy benefits	2,748	1,923
Increase (decrease) in other policyholder liabilities	6,921	(740)
Increase (decrease) in Federal income taxes	8,281	3,298
Increase (decrease) in other liabilities	(7,324)	2,932
Other, net	0	127
Net cash provided by operating activities	82,281	76,004
Proceeds from sales of:
Securities available for sale	609	418
Other investments	2,884	477
Proceeds from maturities and redemptions of:
Securities held to maturity	403,974	384,604
Securities available for sale	66,052	79,767
Index options	14,980	260
Purchases of:
Securities held to maturity	(509,924)	(406,536)
Securities available for sale	(121,242)	(173,237)
Index options	(12,169)	(10,672)
Other investments	(15)	(1,503)
Principal payments on mortgage loans	17,000	4,536
Cost of mortgage loans acquired	(253)	(390)
Decrease (increase) in policy loans	406	318
Other, net	(2)	3
Net cash used in investing activities	(137,700)	(121,955)
Cash flows from financing activities:
Deposits to account balances for universal life and annuity contracts	231,749	212,423
Return of account balances on universal life and annuity contracts	(214,665)	(210,657)
Issuance of common stock under stock option plan	0	0
Net cash provided by financing activities	17,084	1,766
Effect of foreign exchange	590	386
Net increase (decrease) in cash and short-term investments	(37,745)	(43,799)
Cash and short-term investments at beginning of period	124,561	119,290
Cash and short-term investments at end of period	86,816	75,491
Cash paid during the period for:
Interest	20	10
Income taxes	2,484	6,539
Noncash operating activities:
Deferral of sales inducements	$ 714	$ 1,314