Fair Value of Financial Instruments (Carrying Value and Estimated Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Fair Value [Member]
Investments
Held-to-maturity fixed maturities	$ 3,927		$ 4,161
Available-for-sale fixed maturities	2,800,624		2,697,248
Trading securities	14,249		13,454
Equity securities	174,359		159,451
Mortgage loans	5,234		5,219
Policy loans	7,393		7,209
Other long-term investments	24,399		20,574
Short-term investments	1,100		1,100
Cash and cash equivalents	101,978		144,527
Accrued investment income	32,750		32,219
Policy reserves
Annuity (accumulations)	1,114,522	[1]	1,074,661	[1]
Annuity (benefit payments)	144,274		133,921
Debt	45,000		45,000
Carrying Value [Member]
Investments
Held-to-maturity fixed maturities	3,864		4,143
Available-for-sale fixed maturities	2,800,624		2,697,248
Trading securities	14,249		13,454
Equity securities	174,359		159,451
Mortgage loans	4,732		4,829
Policy loans	7,393		7,209
Other long-term investments	24,399		20,574
Short-term investments	1,100		1,100
Cash and cash equivalents	101,978		144,527
Accrued investment income	32,750		32,219
Policy reserves
Annuity (accumulations)	1,008,607	[1]	999,534	[1]
Annuity (benefit payments)	98,579		94,465
Debt	$ 45,000		$ 45,000

[1] Annuity accumulations represent deferred annuity contracts that are currently earning interest.