The sum of insurance premiums earned, premiums earned on the income statement for all insurance and reinsurance contracts after subtracting any amounts ceded to another insurer and adding premiums assumed from other insurers, and contract charges earned on investment and universal life-type contracts.

No definition available.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summarized financial information for these segments
Insurance premiums and contract charges earned													$ 715,760	$ 690,938	$ 670,527
Net investment income													329,815us-gaap_NetInvestmentIncome	313,610us-gaap_NetInvestmentIncome	306,003us-gaap_NetInvestmentIncome
Net income (loss)	30,068us-gaap_NetIncomeLoss	25,357us-gaap_NetIncomeLoss	20,452us-gaap_NetIncomeLoss	28,366us-gaap_NetIncomeLoss	34,287us-gaap_NetIncomeLoss	23,599us-gaap_NetIncomeLoss	25,995us-gaap_NetIncomeLoss	27,012us-gaap_NetIncomeLoss	31,826us-gaap_NetIncomeLoss	32,266us-gaap_NetIncomeLoss	13,103us-gaap_NetIncomeLoss	26,671us-gaap_NetIncomeLoss	104,243us-gaap_NetIncomeLoss	110,893us-gaap_NetIncomeLoss	103,866us-gaap_NetIncomeLoss
Assets	9,768,527us-gaap_Assets				8,826,672us-gaap_Assets				8,167,726us-gaap_Assets				9,768,527us-gaap_Assets	8,826,672us-gaap_Assets	8,167,726us-gaap_Assets
Property and casualty [Member]
Summarized financial information for these segments
Insurance premiums and contract charges earned													581,828	561,954	546,339
Net investment income													36,790	36,208	36,792
Net income (loss)													46,907	44,433	37,043
Assets	1,107,962				1,001,561				1,016,368				1,107,962	1,001,561	1,016,368
Annuity [Member]
Summarized financial information for these segments
Insurance premiums and contract charges earned													25,540	22,575	21,794
Net investment income													222,071	208,419	200,785
Net income (loss)													45,336	44,719	40,527
Assets	6,683,473				5,963,348				5,380,780				6,683,473	5,963,348	5,380,780
Life [Member]
Summarized financial information for these segments
Insurance premiums and contract charges earned													108,392	106,409	102,394
Net investment income													71,865	69,932	69,409
Net income (loss)													17,503	20,339	21,912
Assets	1,858,150				1,743,084				1,663,696				1,858,150	1,743,084	1,663,696
Corporate and other [Member]
Summarized financial information for these segments
Net investment income													14	7	2
Net income (loss)													(5,503)	1,402	4,384
Assets	155,678				154,557				131,449				155,678	154,557	131,449
Intersegment eliminations [Member]
Summarized financial information for these segments
Net investment income													(925)	(956)	(985)
Assets	$ (36,736)				$ (35,878)				$ (24,567)				$ (36,736)	$ (35,878)	$ (24,567)