Fair Value of Financial Instruments (Carrying Value and Estimated Fair Value) (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Investments
Held-to-maturity securities		$ 359	$ 404
Available-for-sale securities		3,055,908	3,088,922
Trading securities		19,987	20,928
Fair Value [Member]
Investments
Mortgage loans		4,388	4,559
Policy loans		5,702	5,916
Other long-term investments		50,656	50,424
Short-term investments		175	175
Cash and cash equivalents		93,382	90,574
Corporate-owned life insurance		1,148	918
Policy reserves
Annuity (accumulations)	[1]	783,329	865,802
Annuity (benefit payments)		130,123	176,592
Fair Value [Member] | Fixed Maturities [Member]
Investments
Held-to-maturity securities		359	404
Available-for-sale securities		2,811,361	2,843,079
Trading securities		16,388	16,862
Fair Value [Member] | Equity Securities [Member]
Investments
Available-for-sale securities		244,547	245,843
Trading securities		3,599	4,066
Carrying Value [Member]
Investments
Mortgage loans		4,082	4,199
Policy loans		5,702	5,916
Other long-term investments		50,656	50,424
Short-term investments		175	175
Cash and cash equivalents		93,382	90,574
Corporate-owned life insurance		1,148	918
Policy reserves
Annuity (accumulations)	[1]	790,701	863,606
Annuity (benefit payments)		95,432	99,121
Carrying Value [Member] | Fixed Maturities [Member]
Investments
Held-to-maturity securities		356	397
Available-for-sale securities		2,811,361	2,843,079
Trading securities		16,388	16,862
Carrying Value [Member] | Equity Securities [Member]
Investments
Available-for-sale securities		244,547	245,843
Trading securities		$ 3,599	$ 4,066

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