AMERISAFE (AMSF) 10-Q 1 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 27, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	AMSF
Entity Registrant Name	AMERISAFE INC
Entity Central Index Key	1018979
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		18,978,693

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investments:
Fixed maturity securities-held-to-maturity, at amortized cost (fair value $711,264 and $664,371 in 2015 and 2014, respectively)	$686,618	$639,631
Fixed maturity securities-available-for-sale, at fair value (cost $357,319 and $327,004 in 2015 and 2014, respectively)	362,804	331,242
Equity securities-available-for-sale, at fair value (cost $0 in 2015 and 2014)	28	28
Short-term investments	12,184	33,684
Other investments	11,729	11,748
Total investments	1,073,363	1,016,333
Cash and cash equivalents	79,731	90,956
Amounts recoverable from reinsurers	87,377	85,888
Premiums receivable, net of allowance	188,281	178,917
Deferred income taxes	30,826	31,231
Accrued interest receivable	12,042	11,637
Property and equipment, net	7,180	7,240
Deferred policy acquisition costs	20,791	19,649
Federal income tax recoverable		1,082
Other assets	15,386	14,287
Total assets	1,514,977	1,457,220
Liabilities:
Reserves for loss and loss adjustment expenses	704,938	687,602
Unearned premiums	172,042	168,576
Reinsurance premiums payable	1,862	843
Amounts held for others	43,298	42,827
Policyholder deposits	47,833	48,722
Insurance-related assessments	30,288	29,315
Accounts payable and other liabilities	32,255	30,110
Payable for investments purchased	20,808	2,257
Total liabilities	1,053,324	1,010,252
Shareholders' equity:
Voting-$0.01 par value authorized shares-50,000,000 in 2015 and 2014; 20,236,943 and 20,155,936 shares issued and 18,978,693 and 18,897,686 shares outstanding in 2015 and 2014, respectively	202	201
Additional paid-in capital	200,714	199,138
Treasury stock at cost (1,258,250 shares in 2015 and 2014)	-22,370	-22,370
Accumulated earnings	279,479	267,189
Accumulated other comprehensive income, net	3,628	2,810
Total shareholders' equity	461,653	446,968
Total liabilities and shareholders' equity	$1,514,977	$1,457,220

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Fixed maturity securities, fair value	$711,264	$664,371
Fixed maturity securities, cost	357,319	327,004
Equity securities, cost	$0	$0
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	20,236,943	20,155,936
Common stock, shares outstanding	18,978,693	18,897,686
Treasury stock, shares	1,258,250	1,258,250

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Income (Unaudited) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues
Gross premiums written	$100,789	$105,703
Ceded premiums written	-2,536	-3,339
Net premiums written	98,253	102,364
Net premiums earned	94,787	89,233
Net investment income	6,833	6,708
Net realized gains on investments	59	101
Fee and other income	109	131
Total revenues	101,788	96,173
Expenses
Loss and loss adjustment expenses incurred	60,006	61,285
Underwriting and certain other operating costs	7,472	7,963
Commissions	7,005	6,687
Salaries and benefits	5,893	6,721
Policyholder dividends	215	113
Total expenses	80,591	82,769
Income before income taxes	21,197	13,404
Income tax expense	6,067	2,855
Net income	15,130	10,549
Net income available to common shareholders	$15,130	$10,549
Earnings per share
Basic	$0.80	$0.57
Diluted	$0.79	$0.56
Shares used in computing earnings per share
Basic	18,847,792	18,531,926
Diluted	19,047,479	18,884,929
Extraordinary cash dividends declared per common share		$0.50
Cash dividends declared per common share	$0.15	$0.12

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$15,130	$10,549
Other comprehensive income:
Unrealized gain on securities, net of tax	818	3,240
Comprehensive income	$15,948	$13,789

Condensed_Consolidated_Stateme2

Condensed Consolidated Statement of Changes in Shareholders' Equity (Unaudited) (USD $)	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
In Thousands, except Share data
Beginning Balance at Dec. 31, 2014	$446,968	$201	($22,370)	$199,138	$267,189	$2,810
Treasury Stock Beginning Balance, Shares at Dec. 31, 2014	-1,258,250		-1,258,250
Beginning Balance, Shares at Dec. 31, 2014	18,897,686	20,155,936
Comprehensive income	15,948				15,130	818
Options exercised	557	1		556
Options exercised, Shares	74,250	74,250
Tax benefit from share-based payments	809			809
Restricted common stock issued	0	0	0	0	0	0
Restricted common stock issued, Shares		6,757
Share-based compensation	211			211
Dividends to stockholders	-2,840				-2,840
Ending Balance at Mar. 31, 2015	$461,653	$202	($22,370)	$200,714	$279,479	$3,628
Treasury Stock Ending Balance, Shares at Mar. 31, 2015	-1,258,250		-1,258,250
Ending Balance, Shares at Mar. 31, 2015	18,978,693	20,236,943

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Activities
Net income	$15,130	$10,549
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	336	332
Net amortization of investments	4,024	3,765
Deferred income taxes	-36	-906
Net realized gains on investments	-59	-101
Share-based compensation	359	558
Changes in operating assets and liabilities:
Premiums receivable, net	-9,364	-21,385
Accrued interest receivable	-405	-103
Deferred policy acquisition costs	-1,142	-1,920
Other assets	613	-1,241
Reserves for loss and loss adjustment expenses	17,336	21,634
Unearned premiums	3,466	13,132
Reinsurance balances	-470	-1,829
Amounts held for others and policyholder deposits	-418	2,069
Accounts payable and other liabilities	2,975	5,732
Net cash provided by operating activities	32,345	30,286
Investing Activities
Purchases of investments held-to-maturity	-55,425	-38,698
Purchases of investments available-for-sale	-49,215	-35,248
Purchases of short-term investments	-4,440	-44,920
Proceeds from maturities of investments held-to-maturity	19,828	24,930
Proceeds from sales and maturities of investments available-for-sale	21,666	14,557
Proceeds from sales and maturities of short-term investments	25,771	43,369
Purchases of property and equipment	-276	-208
Net cash used in investing activities	-42,091	-36,218
Financing Activities
Proceeds from stock option exercises	557	600
Tax benefit from share-based payments	809	625
Dividends to stockholders	-2,845	-11,510
Net cash used in financing activities	-1,479	-10,285
Change in cash and cash equivalents	-11,225	-16,217
Cash and cash equivalents at beginning of period	90,956	123,077
Cash and cash equivalents at end of period	$79,731	$106,860

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Note 1. Basis of Presentation
	AMERISAFE, Inc. (the “Company”) is an insurance holding company incorporated in the state of Texas. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries: American Interstate Insurance Company (“AIIC”), Silver Oak Casualty, Inc. (“SOCI”), American Interstate Insurance Company of Texas (“AIICTX”), Amerisafe Risk Services, Inc. (“RISK”) and Amerisafe General Agency, Inc. (“AGAI”). AIIC and SOCI are property and casualty insurance companies organized under the laws of the state of Nebraska. AIICTX is a property and casualty insurance company organized under the laws of the state of Texas. RISK, a wholly owned subsidiary of the Company, is a claims and safety services company, currently servicing only affiliated insurance companies. AGAI, a wholly owned subsidiary of the Company, is a general agent for the Company. AGAI sells insurance, which is underwritten by AIIC, SOCI and AIICTX, as well as by nonaffiliated insurance carriers. The assets and operations of AGAI are not significant to that of the Company and its consolidated subsidiaries. The terms “AMERISAFE,” the “Company,” “we,” “us” or “our” refer to AMERISAFE, Inc. and its consolidated subsidiaries, as the context requires.
	The Company provides workers’ compensation insurance for small to mid-sized employers engaged in hazardous industries, principally construction, trucking, manufacturing, oil and gas, and agriculture. Assets and revenues of AIIC represent at least 95% of comparable consolidated amounts of the Company for each of 2015 and 2014.
	In the opinion of management of the Company, the accompanying unaudited condensed consolidated financial statements contain all adjustments (consisting of normal recurring accruals) necessary to present fairly the financial position, the results of operations and cash flows for the periods presented. The unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q under the Securities Exchange Act of 1934 and therefore do not include all information and footnotes to be in conformity with accounting principles generally accepted in the United States (“GAAP”). The results for the interim periods are not necessarily indicative of the results of operations that may be expected for the year. The unaudited condensed consolidated financial statements contained herein should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2014.
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Certain prior year amounts have been reclassified to conform with the current year presentation.

Stock_Options_and_Restricted_S

Stock Options and Restricted Stock	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Options and Restricted Stock	Note 2. Stock Options and Restricted Stock
	The Company has three equity incentive plans: the AMERISAFE 2005 Equity Incentive Plan (the “2005 Incentive Plan”), the AMERISAFE 2010 Non-Employee Director Restricted Stock Plan (the “2010 Restricted Stock Plan”) and the AMERISAFE 2012 Equity and Incentive Compensation Plan (the “2012 Incentive Plan”). See Note 12 to our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2014 for additional information regarding the Company’s incentive plans.
	In March 2015, the Company granted 6,757 shares of restricted common stock to executive officers. The market value of the restricted shares granted totaled $0.3 million.
	During the three months ended March 31, 2015, options to purchase 74,250 shares of common stock were exercised. During the three months ended March 31, 2014, options to purchase 61,167 shares of common stock were exercised. In connection with these exercises, the Company received $0.6 million of stock option proceeds in both 2015 and 2014.
	The Company recognized share-based compensation expense of $0.4 million in the three months ended March 31, 2015 and $0.6 million for the same period of 2014.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Note 3. Earnings Per Share
	The Company computes earnings per share (“EPS”) in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 260, Earnings Per Share. The Company has no participating unvested common shares which contain nonforfeitable rights to dividends and applies the treasury stock method in computing basic and diluted earnings per share.
	Basic EPS is calculated by dividing income available to common shareholders by the weighted-average number of common shares outstanding during the period. The diluted EPS calculation includes potential common shares assumed issued under the treasury stock method, which reflects the potential dilution that would occur if any outstanding options or warrants were exercised or restricted stock becomes vested, and includes the “if converted” method for participating securities if the effect is dilutive.
		Three Months Ended
		March 31,
		2015		2014
		(in thousands, except share and
		per share amounts)
	Basic EPS:
	Net income available to common shareholders - basic	$	15,130	$	10,549
	Basic weighted average common shares		18,847,792		18,531,926
	Basic earnings per common share	$	0.8	$	0.57
	Diluted EPS:
	Net income available to common shareholders - diluted	$	15,130	$	10,549
	Diluted weighted average common shares:
	Weighted average common shares		18,847,792		18,531,926
	Stock options and performance shares		199,687		353,003
	Diluted weighted average common shares		19,047,479		18,884,929
	Diluted earnings per common share	$	0.79	$	0.56

Investments

Investments	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	Note 4. Investments
	The gross unrealized gains and losses on, and the amortized cost and fair value of, those investments classified as held-to-maturity at March 31, 2015 are summarized as follows:
			Amortized Cost		Gross		Gross			Fair Value
					Unrealized		Unrealized
					Gains		Losses
			(in thousands)
	States and political subdivisions		$	417,361	$	19,559	$	(46	)	$	436,874
	Corporate bonds			191,594		812		(207	)		192,199
	Commercial mortgage-backed securities			46,094		1,495		—			47,589
	U.S. agency-based mortgage-backed securities			15,953		1,691		(2	)		17,642
	U.S. Treasury securities and obligations of U.S. Government agencies			12,932		1,176		—			14,108
	Asset-backed securities			2,684		246		(78	)		2,852
	Totals		$	686,618	$	24,979	$	(333	)	$	711,264
	The gross unrealized gains and losses on, and the cost or amortized cost and fair value of, those investments classified as available-for-sale at March 31, 2015 are summarized as follows:
			Cost or		Gross		Gross			Fair Value
			Amortized		Unrealized		Unrealized
			Cost		Gains		Losses
			(in thousands)
	Fixed maturity:
	States and political subdivisions		$	168,277	$	7,634	$	(2,189	)	$	173,722
	Corporate bonds			179,275		1,026		(154	)		180,147
	U.S. agency-based mortgage-backed securities			9,767		4		(836	)		8,935
	Total fixed maturity			357,319		8,664		(3,179	)		362,804
	Other investments			10,000		1,729		—			11,729
	Equity securities			—		28		—			28
	Totals		$	367,319	$	10,421	$	(3,179	)	$	374,561
	The gross unrealized gains and losses on, and the amortized cost and fair value of, those investments classified as held-to-maturity at December 31, 2014 are summarized as follows:
			Amortized Cost		Gross		Gross			Fair Value
					Unrealized		Unrealized
					Gains		Losses
			(in thousands)
	States and political subdivisions		$	385,623	$	20,100	$	(58	)	$	405,665
	Corporate bonds			176,880		374		(520	)		176,734
	Commercial mortgage-backed securities			46,662		1,867		—			48,529
	U.S. agency-based mortgage-backed securities			16,972		1,702		(2	)		18,672
	U.S. Treasury securities and obligations of U.S. Government agencies			10,697		1,097		(2	)		11,792
	Asset-backed securities			2,797		264		(82	)		2,979
	Totals		$	639,631	$	25,404	$	(664	)	$	664,371
	The gross unrealized gains and losses on, and the cost or amortized cost and fair value of, those investments classified as available-for-sale at December 31, 2014 are summarized as follows:
			Cost or		Gross		Gross			Fair Value
			Amortized		Unrealized		Unrealized
			Cost		Gains		Losses
			(in thousands)
	Fixed maturity:
	States and political subdivisions		$	151,744	$	7,302	$	(1,672	)	$	157,374
	Corporate bonds			165,412		428		(470	)		165,370
	U.S. agency-based mortgage-backed securities			9,848		2		(1,352	)		8,498
	Total fixed maturity			327,004		7,732		(3,494	)		331,242
	Other investments			10,000		1,748		—			11,748
	Equity securities			—		28		—			28
	Totals		$	337,004	$	9,508	$	(3,494	)	$	343,018
	A summary of the cost and fair value of investments in fixed maturity securities, classified as held-to-maturity at March 31, 2015, by contractual maturity, is as follows:
	Remaining Time to Maturity		Amortized		Fair Value
			Cost Basis
			(in thousands)
	Within one year		$	142,860	$	143,563
	After one year through five years			282,666		292,645
	After five years through ten years			114,203		121,383
	After ten years			82,158		85,590
	U.S. agency-based mortgage-backed securities			15,953		17,642
	Commercial mortgage-backed securities			46,094		47,589
	Asset-backed securities			2,684		2,852
	Total		$	686,618	$	711,264
	A summary of cost and fair value of investments in fixed maturity securities, classified as available-for-sale at March 31, 2015, by contractual maturity, is as follows:
Remaining Time to Maturity		Amortized		Fair Value
		Cost Basis
		(in thousands)
Within one year		$	54,548	$	54,603
After one year through five years			145,418		146,672
After five years through ten years			17,163		17,429
After ten years			130,423		135,165
U.S. agency-based mortgage-backed securities			9,767		8,935
Total		$	357,319	$	362,804
The following table summarizes the fair value and gross unrealized losses on securities, aggregated by major investment category and length of time that the individual securities have been in a continuous unrealized loss position:
		Less Than 12 Months				12 Months or Greater					Total
		Fair Value of		Gross		Fair Value of			Gross		Fair Value of		Gross
		Investments		Unrealized		Investments			Unrealized		Investments		Unrealized
		with		Losses		with			Losses		with		Losses
		Unrealized				Unrealized					Unrealized
		Losses				Losses					Losses
		(in thousands)
March 31, 2015
Held-to-Maturity
Fixed maturity securities:
Corporate bonds		$	76,863	$	200	$	4,280		$	7	$	81,143	$	207
States and political subdivisions			18,113		46		—			—		18,113		46
U.S. agency-based mortgage-backed securities			89		2		—			—		89		2
Asset-backed securities			—		—		1,613			78		1,613		78
Total held-to-maturity securities			95,065		248		5,893			85		100,958		333
Available-for Sale
Fixed maturity securities:
Corporate bonds		$	52,767	$	150	$	1,028		$	4	$	53,795	$	154
States and political subdivisions			4,200		22		9,888			2,167		14,088		2,189
U.S. agency-based mortgage-backed securities			—		—		8,827			836		8,827		836
Total available-for-sale securities			56,967		172		19,743			3,007		76,710		3,179
Total		$	152,032	$	420	$	25,636		$	3,092	$	177,668	$	3,512
December 31, 2014
Held-to-Maturity
Fixed maturity securities:
Corporate bonds		$	129,788	$	520	$	—		$	—	$	129,788	$	520
States and political subdivisions			16,896		58		—			—		16,896		58
U.S. Treasury securities and obligations of U.S. Government agencies			3,385		2		—			—		3,385		2
U.S. agency-based mortgage-backed securities			78		2		—			—		78		2
Asset-backed securities			—		—		1,662			82		1,662		82
Total held-to-maturity securities			150,147		582		1,662			82		151,809		664
Available-for Sale
Fixed maturity securities:
Corporate bonds		$	106,185	$	470	$	—		$	—	$	106,185	$	470
States and political subdivisions			3,810		6		10,347			1,666		14,157		1,672
U.S. agency-based mortgage-backed securities			627		11		7,757			1,341		8,384		1,352
Total available-for-sale securities			110,622		487		18,104			3,007		128,726		3,494
Total		$	260,769	$	1,069	$	19,766		$	3,089	$	280,535	$	4,158
At March 31, 2015, the Company held 112 individual fixed maturity securities that were in an unrealized loss position, of which 22 individual fixed maturity securities were in a continuous unrealized loss position for longer than 12 months.
The Company holds investments in a long/short equity fund, accounted for under the equity method. The carrying value of this investment is $11.7 million at March 31, 2015.
Investment income is recognized as it is earned. The discount or premium on fixed maturity securities is amortized using the “constant yield” method. Anticipated prepayments, where applicable, are considered when determining the amortization of premiums or discounts. Realized investment gains and losses are determined using the specific identification method.
We regularly review our investment portfolio to evaluate the necessity of recording impairment losses for other-than-temporary declines in the fair value of specific investments. We consider various factors in determining if a decline in the fair value of an individual security is other-than-temporary. The key factors we consider are:
	•		any reduction or elimination of preferred dividends, or nonpayment of scheduled principal or interest payments;
	•		the financial condition and near-term prospects of the issuer of the applicable security, including any specific events that may affect its operations or earnings;
	•		how long and by how much the fair value of the security has been below its cost or amortized cost;
	•		any downgrades of the security by a rating agency;
	•		our intent not to sell the security for a sufficient time period for it to recover its value;
	•		the likelihood of being forced to sell the security before the recovery of its value; and
	•		an evaluation as to whether there are any credit losses on debt securities.
We reviewed all securities with unrealized losses in accordance with the impairment policy described above. The Company expects to hold investments in equity securities for a reasonable period of time sufficient for a recovery of fair value. The Company determined that the unrealized losses in the fixed maturity securities portfolio related primarily to changes in market interest rates since the date of purchase, current conditions in the capital markets and the impact of those conditions on market liquidity and prices generally, and the transfer of the investments from the available-for-sale classification to the held-to-maturity classification in January 2004. We expect to recover the carrying value of these securities as it is not more likely than not that we will be required to sell the security before the recovery of its amortized cost basis.
Net realized gains in the three months ended March 31, 2015 were $0.1 million resulting from gains on called fixed maturity securities. Net realized gains on investments in the three months ended March 31, 2014 were $0.1 million resulting from gains on called fixed maturity securities and the sale of equity securities.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Note 5. Income Taxes
	In accordance with FASB ASC Topic 740, “Income Taxes,” we provide for the recognition and measurement of deferred income tax benefits based on the likelihood of their realization in future years. As of March 31, 2015, the Company had no material unrecognized tax benefits and no adjustments to liabilities or operations were required.
	The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. There were no uncertain tax positions recognized for the periods ended March 31, 2015 and 2014.
	Tax years 2011 through 2014 are subject to examination by the federal and state taxing authorities.

Comprehensive_Income_and_Accum

Comprehensive Income and Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Comprehensive Income and Accumulated Other Comprehensive Income	Note 6. Comprehensive Income and Accumulated Other Comprehensive Income
	Comprehensive income was $15.9 million for the three months ended March 31, 2015, compared to $13.8 million for the three months ended March 31, 2014. The difference between net income as reported and comprehensive income was due to changes in unrealized gains and losses, net of tax on available-for-sale securities.
	Comprehensive income includes net income plus unrealized gains/losses on our available-for-sale investment securities, net of tax. In reporting comprehensive income on a net basis in the statement of income, we used a 35 percent tax rate. The following table illustrates the changes in the balance of each component of accumulated other comprehensive income for each period presented in the interim financial statements.
		Three Months Ended
		March 31,
		2015			2014
		(in thousands)
	Beginning balance	$	2,810		$	(4,295	)
	Other comprehensive income before reclassification		883			3,134
	Amounts reclassified from accumulated other comprehensive income		(65	)		106
	Net current period other comprehensive income		818			3,240
	Ending balance	$	3,628		$	(1,055	)
	The sale or other-than-temporary impairment of an available-for-sale security results in amounts being reclassified from accumulated other comprehensive income to current period net income. The effects of reclassifications out of accumulated other comprehensive income by the respective line items of net income are presented in the following table.
	Component of Accumulated Other Comprehensive	Three Months Ended						Affected line item in the statement of income
	Income	March 31,
		2015			2014
		(in thousands)
	Unrealized gains/losses on available-for-sale securities	$	100		$	(163	)	Net realized gains on investments
			100			(163	)	Income before income taxes
			(35	)		57		Income tax expense
		$	65		$	(106	)	Net income

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 7. Fair Value Measurements
	We carry available-for-sale securities at fair value in our consolidated financial statements and determine fair value measurements and disclosure in accordance with FASB ASC Topic 820, “Fair Value Measurements and Disclosures.”
	The Company determines the fair values of its financial instruments based on the fair value hierarchy established in ASC Topic 820, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard defines fair value, describes three levels of inputs that may be used to measure fair value, and expands disclosures about fair value measurements.
	Fair value is defined in ASC Topic 820 as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is the price to sell an asset or transfer a liability and, therefore, represents an exit price, not an entry price. Fair value is the exit price in the principal market (or, if lacking a principal market, the most advantageous market) in which the reporting entity would transact. Fair value is a market-based measurement, not an entity-specific measurement, and, as such, is determined based on the assumptions that market participants would use in pricing the asset or liability. The exit price objective of a fair value measurement applies regardless of the reporting entity’s intent and/or ability to sell the asset or transfer the liability at the measurement date.
	ASC Topic 820 requires the use of valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets and liabilities. The income approach uses valuation techniques to convert future amounts, such as cash flows or earnings, to a single present value amount on a discounted basis. The cost approach is based on the amount that currently would be required to replace the service capacity of an asset, also known as current replacement cost. Valuation techniques used to measure fair value are to be consistently applied.
	In ASC Topic 820, inputs refer broadly to the assumptions that market participants would use in pricing the asset or liability, including assumptions about risk, for example, the risk inherent in a particular valuation technique used to measure fair value (such as a pricing model) and/or the risk inherent in the inputs to the valuation technique. Inputs may be observable or unobservable:
		•		Observable inputs are inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the reporting entity.
		•		Unobservable inputs are inputs that reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances.
	Valuation techniques used to measure fair value are intended to maximize the use of observable inputs and minimize the use of unobservable inputs. ASC Topic 820 establishes a fair value hierarchy that prioritizes the use of inputs used in valuation techniques into the following three levels:
		•		Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date.
		•		Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, or inputs that are derived principally from or corroborated by observable market data.
		•		Level 3 inputs are unobservable inputs for the asset or liability. Unobservable inputs are to be used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date.
	In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market-based parameters.
	The fair values of the Company’s investments are based upon prices provided by an independent pricing service. The Company has reviewed these prices for reasonableness and has not adjusted any prices received from the independent provider. Securities reported at fair value utilizing Level 1 inputs represent assets whose fair value is determined based upon observable unadjusted quoted market prices for identical assets in active markets. Level 2 securities represent assets whose fair value is determined using observable market information such as previous day trade prices, quotes from less active markets or quoted prices of securities with similar characteristics. There were no transfers between Level 1 and Level 2 during the three months ended March 31, 2015.
	At March 31, 2015, assets and liabilities measured at fair value on a recurring basis are summarized below:
			Level 1			Level 2		Level 3		Total Fair
			Inputs			Inputs		Inputs		Value
			(in thousands)
	Financial instruments carried at fair value, classified as a part of:
	Other investments		$	—		$	—	$	11,729	$	11,729
	Securities available for sale—equity:
	Domestic common stock			28			—		—		28
	Securities available for sale—fixed maturity:
	States and political subdivisions			—			173,722		—		173,722
	Corporate bonds			—			180,147		—		180,147
	U.S. agency-based mortgage-backed securities			—			8,935		—		8,935
	Total securities available for sale—fixed maturity			—			362,804		—		362,804
	Total available for sale		$	28		$	362,804	$	11,729	$	374,561
	At March 31, 2015, assets and liabilities measured at amortized cost are summarized below:
			Level 1			Level 2		Level 3		Total Fair
			Inputs			Inputs		Inputs		Value
			(in thousands)
	Securities held-to-maturity—fixed maturity
	States and political subdivisions		$	—		$	436,874	$	—	$	436,874
	Corporate bonds			—			192,199		—		192,199
	Commercial mortgage-backed securities			—			47,589		—		47,589
	U.S. agency-based mortgage-backed securities			—			17,642		—		17,642
	U.S. Treasury securities			14,108			—		—		14,108
	Asset-backed securities			—			2,852		—		2,852
	Total held-to-maturity		$	14,108		$	697,156	$	—	$	711,264
	At December 31, 2014, assets and liabilities measured at fair value on a recurring basis are summarized below:
			December 31, 2014
			Level 1			Level 2		Level 3		Total Fair
			Inputs			Inputs		Inputs		Value
			(in thousands)
	Financial instruments carried at fair value, classified as part of:
	Other investments		$	—		$	—	$	11,748	$	11,748
	Securities available for sale—equity:
	Domestic common stock			28			—		—		28
	Securities available for sale—fixed maturity:
	States and political subdivisions			—			157,374		—		157,374
	U.S. agency-based mortgage-backed securities			—			8,498		—		8,498
	Corporate bonds			—			165,370		—		165,370
	Total available for sale—fixed maturity		$	—		$	331,242	$	—	$	331,242
	Total available for sale		$	28		$	331,242	$	11,748	$	343,018
	At December 31, 2014, assets and liabilities measured at amortized cost are summarized below:
			December 31, 2014
			Level 1			Level 2		Level 3		Total Fair
			Inputs			Inputs		Inputs		Value
			(in thousands)
	Securities held-to-maturity—fixed maturity:
	States and political subdivisions		$	—		$	405,665	$	—	$	405,665
	Corporate bonds			—			176,734		—		176,734
	Commercial mortgage-backed securities			—			48,529		—		48,529
U.S. agency-based mortgage-backed securities			—			18,672		—		18,672
U.S. Treasury securities			11,792			—		—		11,792
Asset-backed securities			—			2,979		—		2,979
Total held-to-maturity		$	11,792		$	652,579	$	—	$	664,371
The Company determines fair value amounts for financial instruments using available third-party market information. When such information is not available, the Company determines the fair value amounts using appropriate valuation methodologies. Nonfinancial instruments such as real estate, property and equipment, deferred policy acquisition costs, deferred income taxes and loss and loss adjustment expense reserves are excluded from the fair value disclosure.
Cash and Cash Equivalents—The carrying amounts reported in the accompanying consolidated balance sheets for these financial instruments approximate their fair values, which are characterized as Level 1 assets.
Investments—The fair values for fixed maturity and equity securities are based on prices obtained from an independent pricing service. Equity and treasury securities are characterized as Level 1 assets, as their fair values are based on quoted prices in active markets. Fixed maturity securities, other than treasury securities, are characterized as Level 2 assets, as their fair values are determined using observable market inputs.
Short Term Investments—The carrying amounts reported in the accompanying consolidated balance sheets for these financial instruments approximate their fair values. These securities are characterized as Level 2 assets in the fair value hierarchy.
Other Investments—Other investments consist of limited partnership (LP) interests valued using the net asset value provided by the general partner of the LP, which approximates the fair value of the interest. The LP’s objective is to generate absolute returns by investing long and short in publicly-traded global securities. Redemptions are allowed monthly following a sixty day notice with no lock up periods. The Company has no unfunded commitments related to the LP. This investment is characterized as a Level 3 asset in the fair value hierarchy.
The following table summarizes the carrying values and corresponding fair values for financial instruments:
		As of March 31, 2015					As of December 31, 2014
		Carrying			Fair		Carrying		Fair
		Amount			Value		Amount		Value
		(in thousands)
Assets:
Fixed maturity securities—held-to-maturity		$	686,618		$	711,264	$	639,631	$	664,371
Fixed maturity securities—available-for-sale			362,804			362,804		331,242		331,242
Equity securities			28			28		28		28
Cash and cash equivalents			79,731			79,731		90,956		90,956
Short-term investments			12,184			12,184		33,684		33,684
Other investments			11,729			11,729		11,748		11,748
The following table presents summary information regarding changes in the fair value of assets measured at fair value using Level 3 input.
		March 31, 2015			December 31, 2014
		(in thousands)
Beginning balance		$	11,748		$	10,591
Total unrealized gains/(losses)			(19	)		1,157
Ending balance		$	11,729		$	11,748

Treasury_Stock

Treasury Stock	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Treasury Stock	Note 8. Treasury Stock
	The Company’s Board of Directors initiated a share repurchase program in February 2010. In October 2011, 2012, 2013 and 2014, the Board reauthorized this program with a limit of $25.0 million. Unless reauthorized, the program will expire on December 31, 2015. Since the beginning of this plan, the Company has repurchased a total of 1,258,250 shares for $22.4 million, or an average price of $17.78, including commissions.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Note 9. Subsequent Events
	On April 28, 2015, the Company’s Board of Directors declared a quarterly cash dividend of $0.15 per share payable on June 26, 2015 to shareholders of record as of June 12, 2015. The Board intends to consider the payment of a regular cash dividend each calendar quarter.

Fair_Value_Measurements_Polici

Fair Value Measurements (Policies)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	We carry available-for-sale securities at fair value in our consolidated financial statements and determine fair value measurements and disclosure in accordance with FASB ASC Topic 820, “Fair Value Measurements and Disclosures.”
	The Company determines the fair values of its financial instruments based on the fair value hierarchy established in ASC Topic 820, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard defines fair value, describes three levels of inputs that may be used to measure fair value, and expands disclosures about fair value measurements.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Calculation of Basic and Diluted Earnings Per Share
		Three Months Ended
		March 31,
		2015		2014
		(in thousands, except share and
		per share amounts)
	Basic EPS:
	Net income available to common shareholders - basic	$	15,130	$	10,549
	Basic weighted average common shares		18,847,792		18,531,926
	Basic earnings per common share	$	0.8	$	0.57
	Diluted EPS:
	Net income available to common shareholders - diluted	$	15,130	$	10,549
	Diluted weighted average common shares:
	Weighted average common shares		18,847,792		18,531,926
	Stock options and performance shares		199,687		353,003
	Diluted weighted average common shares		19,047,479		18,884,929
	Diluted earnings per common share	$	0.79	$	0.56

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2015
Gross Unrealized Gains and Losses and Amortized Cost and Fair Value of Investments Classified as Held-to-maturity	The gross unrealized gains and losses on, and the amortized cost and fair value of, those investments classified as held-to-maturity at March 31, 2015 are summarized as follows:
		Amortized Cost		Gross		Gross			Fair Value
				Unrealized		Unrealized
				Gains		Losses
		(in thousands)
	States and political subdivisions	$	417,361	$	19,559	$	(46	)	$	436,874
	Corporate bonds		191,594		812		(207	)		192,199
	Commercial mortgage-backed securities		46,094		1,495		—			47,589
	U.S. agency-based mortgage-backed securities		15,953		1,691		(2	)		17,642
	U.S. Treasury securities and obligations of U.S. Government agencies		12,932		1,176		—			14,108
	Asset-backed securities		2,684		246		(78	)		2,852
	Totals	$	686,618	$	24,979	$	(333	)	$	711,264
	The gross unrealized gains and losses on, and the amortized cost and fair value of, those investments classified as held-to-maturity at December 31, 2014 are summarized as follows:
		Amortized Cost		Gross		Gross			Fair Value
				Unrealized		Unrealized
				Gains		Losses
		(in thousands)
	States and political subdivisions	$	385,623	$	20,100	$	(58	)	$	405,665
	Corporate bonds		176,880		374		(520	)		176,734
	Commercial mortgage-backed securities		46,662		1,867		—			48,529
	U.S. agency-based mortgage-backed securities		16,972		1,702		(2	)		18,672
	U.S. Treasury securities and obligations of U.S. Government agencies		10,697		1,097		(2	)		11,792
	Asset-backed securities		2,797		264		(82	)		2,979
	Totals	$	639,631	$	25,404	$	(664	)	$	664,371
Gross Unrealized Gains and Losses and Cost or Amortized Cost and Fair Value of Investments Classified as Available-for-sale	The gross unrealized gains and losses on, and the cost or amortized cost and fair value of, those investments classified as available-for-sale at March 31, 2015 are summarized as follows:
		Cost or		Gross		Gross			Fair Value
		Amortized		Unrealized		Unrealized
		Cost		Gains		Losses
		(in thousands)
	Fixed maturity:
	States and political subdivisions	$	168,277	$	7,634	$	(2,189	)	$	173,722
	Corporate bonds		179,275		1,026		(154	)		180,147
	U.S. agency-based mortgage-backed securities		9,767		4		(836	)		8,935
	Total fixed maturity		357,319		8,664		(3,179	)		362,804
	Other investments		10,000		1,729		—			11,729
	Equity securities		—		28		—			28
	Totals	$	367,319	$	10,421	$	(3,179	)	$	374,561
	The gross unrealized gains and losses on, and the cost or amortized cost and fair value of, those investments classified as available-for-sale at December 31, 2014 are summarized as follows:
		Cost or		Gross		Gross			Fair Value
		Amortized		Unrealized		Unrealized
		Cost		Gains		Losses
		(in thousands)
	Fixed maturity:
	States and political subdivisions	$	151,744	$	7,302	$	(1,672	)	$	157,374
	Corporate bonds		165,412		428		(470	)		165,370
	U.S. agency-based mortgage-backed securities		9,848		2		(1,352	)		8,498
	Total fixed maturity		327,004		7,732		(3,494	)		331,242
	Other investments		10,000		1,748		—			11,748
	Equity securities		—		28		—			28
	Totals	$	337,004	$	9,508	$	(3,494	)	$	343,018
Investment Securities Continuous Unrealized Loss Position	The following table summarizes the fair value and gross unrealized losses on securities, aggregated by major investment category and length of time that the individual securities have been in a continuous unrealized loss position:
		Less Than 12 Months				12 Months or Greater					Total
		Fair Value of		Gross		Fair Value of			Gross		Fair Value of		Gross
		Investments		Unrealized		Investments			Unrealized		Investments		Unrealized
		with		Losses		with			Losses		with		Losses
		Unrealized				Unrealized					Unrealized
		Losses				Losses					Losses
		(in thousands)
	March 31, 2015
	Held-to-Maturity
	Fixed maturity securities:
	Corporate bonds	$	76,863	$	200	$	4,280		$	7	$	81,143	$	207
	States and political subdivisions		18,113		46		—			—		18,113		46
	U.S. agency-based mortgage-backed securities		89		2		—			—		89		2
	Asset-backed securities		—		—		1,613			78		1,613		78
	Total held-to-maturity securities		95,065		248		5,893			85		100,958		333
	Available-for Sale
	Fixed maturity securities:
	Corporate bonds	$	52,767	$	150	$	1,028		$	4	$	53,795	$	154
	States and political subdivisions		4,200		22		9,888			2,167		14,088		2,189
	U.S. agency-based mortgage-backed securities		—		—		8,827			836		8,827		836
	Total available-for-sale securities		56,967		172		19,743			3,007		76,710		3,179
	Total	$	152,032	$	420	$	25,636		$	3,092	$	177,668	$	3,512
	December 31, 2014
	Held-to-Maturity
	Fixed maturity securities:
	Corporate bonds	$	129,788	$	520	$	—		$	—	$	129,788	$	520
	States and political subdivisions		16,896		58		—			—		16,896		58
	U.S. Treasury securities and obligations of U.S. Government agencies		3,385		2		—			—		3,385		2
	U.S. agency-based mortgage-backed securities		78		2		—			—		78		2
	Asset-backed securities		—		—		1,662			82		1,662		82
	Total held-to-maturity securities		150,147		582		1,662			82		151,809		664
	Available-for Sale
	Fixed maturity securities:
	Corporate bonds	$	106,185	$	470	$	—		$	—	$	106,185	$	470
	States and political subdivisions		3,810		6		10,347			1,666		14,157		1,672
	U.S. agency-based mortgage-backed securities		627		11		7,757			1,341		8,384		1,352
	Total available-for-sale securities		110,622		487		18,104			3,007		128,726		3,494
	Total	$	260,769	$	1,069	$	19,766		$	3,089	$	280,535	$	4,158
Held-to-Maturity Securities [Member]
Summary of Amortized Cost and Fair Value of Investments in Fixed Maturity Securities, by Contractual Maturity	A summary of the cost and fair value of investments in fixed maturity securities, classified as held-to-maturity at March 31, 2015, by contractual maturity, is as follows:
	Remaining Time to Maturity	Amortized		Fair Value
		Cost Basis
		(in thousands)
	Within one year	$	142,860	$	143,563
	After one year through five years		282,666		292,645
	After five years through ten years		114,203		121,383
	After ten years		82,158		85,590
	U.S. agency-based mortgage-backed securities		15,953		17,642
	Commercial mortgage-backed securities		46,094		47,589
	Asset-backed securities		2,684		2,852
	Total	$	686,618	$	711,264
Available-for-Sale Securities [Member]
Summary of Amortized Cost and Fair Value of Investments in Fixed Maturity Securities, by Contractual Maturity	A summary of cost and fair value of investments in fixed maturity securities, classified as available-for-sale at March 31, 2015, by contractual maturity, is as follows:
	Remaining Time to Maturity	Amortized		Fair Value
		Cost Basis
		(in thousands)
	Within one year	$	54,548	$	54,603
	After one year through five years		145,418		146,672
	After five years through ten years		17,163		17,429
	After ten years		130,423		135,165
	U.S. agency-based mortgage-backed securities		9,767		8,935
	Total	$	357,319	$	362,804

Comprehensive_Income_and_Accum1

Comprehensive Income and Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Income (AOCI)	The following table illustrates the changes in the balance of each component of accumulated other comprehensive income for each period presented in the interim financial statements.
		Three Months Ended
		March 31,
		2015			2014
		(in thousands)
	Beginning balance	$	2,810		$	(4,295	)
	Other comprehensive income before reclassification		883			3,134
	Amounts reclassified from accumulated other comprehensive income		(65	)		106
	Net current period other comprehensive income		818			3,240
	Ending balance	$	3,628		$	(1,055	)
Reclassification Out of Accumulated Other Comprehensive Income	The effects of reclassifications out of accumulated other comprehensive income by the respective line items of net income are presented in the following table.
	Component of Accumulated Other Comprehensive	Three Months Ended						Affected line item in the statement of income
	Income	March 31,
		2015			2014
		(in thousands)
	Unrealized gains/losses on available-for-sale securities	$	100		$	(163	)	Net realized gains on investments
			100			(163	)	Income before income taxes
			(35	)		57		Income tax expense
		$	65		$	(106	)	Net income

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	At March 31, 2015, assets and liabilities measured at fair value on a recurring basis are summarized below:
		Level 1			Level 2		Level 3		Total Fair
		Inputs			Inputs		Inputs		Value
		(in thousands)
	Financial instruments carried at fair value, classified as a part of:
	Other investments	$	—		$	—	$	11,729	$	11,729
	Securities available for sale—equity:
	Domestic common stock		28			—		—		28
	Securities available for sale—fixed maturity:
	States and political subdivisions		—			173,722		—		173,722
	Corporate bonds		—			180,147		—		180,147
	U.S. agency-based mortgage-backed securities		—			8,935		—		8,935
	Total securities available for sale—fixed maturity		—			362,804		—		362,804
	Total available for sale	$	28		$	362,804	$	11,729	$	374,561
	At December 31, 2014, assets and liabilities measured at fair value on a recurring basis are summarized below:
		December 31, 2014
		Level 1			Level 2		Level 3		Total Fair
		Inputs			Inputs		Inputs		Value
		(in thousands)
	Financial instruments carried at fair value, classified as part of:
	Other investments	$	—		$	—	$	11,748	$	11,748
	Securities available for sale—equity:
	Domestic common stock		28			—		—		28
	Securities available for sale—fixed maturity:
	States and political subdivisions		—			157,374		—		157,374
	U.S. agency-based mortgage-backed securities		—			8,498		—		8,498
	Corporate bonds		—			165,370		—		165,370
	Total available for sale—fixed maturity	$	—		$	331,242	$	—	$	331,242
	Total available for sale	$	28		$	331,242	$	11,748	$	343,018
Schedule of Assets and Liabilities Measured at Amortized Cost	At March 31, 2015, assets and liabilities measured at amortized cost are summarized below:
		Level 1			Level 2		Level 3		Total Fair
		Inputs			Inputs		Inputs		Value
		(in thousands)
	Securities held-to-maturity—fixed maturity
	States and political subdivisions	$	—		$	436,874	$	—	$	436,874
	Corporate bonds		—			192,199		—		192,199
	Commercial mortgage-backed securities		—			47,589		—		47,589
	U.S. agency-based mortgage-backed securities		—			17,642		—		17,642
	U.S. Treasury securities		14,108			—		—		14,108
	Asset-backed securities		—			2,852		—		2,852
	Total held-to-maturity	$	14,108		$	697,156	$	—	$	711,264
	At December 31, 2014, assets and liabilities measured at amortized cost are summarized below:
		December 31, 2014
		Level 1			Level 2		Level 3		Total Fair
		Inputs			Inputs		Inputs		Value
		(in thousands)
	Securities held-to-maturity—fixed maturity:
	States and political subdivisions	$	—		$	405,665	$	—	$	405,665
	Corporate bonds		—			176,734		—		176,734
	Commercial mortgage-backed securities		—			48,529		—		48,529
	U.S. agency-based mortgage-backed securities		—			18,672		—		18,672
	U.S. Treasury securities		11,792			—		—		11,792
	Asset-backed securities		—			2,979		—		2,979
	Total held-to-maturity	$	11,792		$	652,579	$	—	$	664,371
Summary of Carrying Values and Corresponding Fair Values for Financial Instruments	The following table summarizes the carrying values and corresponding fair values for financial instruments:
		As of March 31, 2015					As of December 31, 2014
		Carrying			Fair		Carrying		Fair
		Amount			Value		Amount		Value
		(in thousands)
	Assets:
	Fixed maturity securities—held-to-maturity	$	686,618		$	711,264	$	639,631	$	664,371
	Fixed maturity securities—available-for-sale		362,804			362,804		331,242		331,242
	Equity securities		28			28		28		28
	Cash and cash equivalents		79,731			79,731		90,956		90,956
	Short-term investments		12,184			12,184		33,684		33,684
	Other investments		11,729			11,729		11,748		11,748
Summary of Changes in Fair Value of Assets Measured at Fair value	The following table presents summary information regarding changes in the fair value of assets measured at fair value using Level 3 input.
		March 31, 2015			December 31, 2014
		(in thousands)
	Beginning balance	$	11,748		$	10,591
	Total unrealized gains/(losses)		(19	)		1,157
	Ending balance	$	11,729		$	11,748

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Percentage of comparable consolidated amounts	95.00%	95.00%

Stock_Options_and_Restricted_S1

Stock Options and Restricted Stock - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
	Incentive_Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans	3
Market value of restricted shares granted	$300,000
Stock options exercised, Shares	74,250	61,167
Proceeds from stock option exercises	557,000	600,000
Share-based compensation expense	$400,000	$600,000
Restricted Stock Units (RSUs) [Member] | Executive Officers [Member] | 2012 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock granted	6,757

Earnings_Per_Share_Calculation

Earnings Per Share - Calculation of Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share, Basic [Abstract]
Net income available to common shareholders - basic	$15,130	$10,549
Basic weighted average common shares	18,847,792	18,531,926
Basic earnings per common share	$0.80	$0.57
Net income available to common shareholders - diluted	$15,130	$10,549
Weighted average common shares	18,847,792	18,531,926
Stock options and performance shares	199,687	353,003
Diluted weighted average common shares	19,047,479	18,884,929
Diluted earnings per common share	$0.79	$0.56

Investments_Gross_Unrealized_G

Investments - Gross Unrealized Gains and Losses and Amortized Cost and Fair Value of Investments Classified as Held-to-Maturity (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment [Line Items]
Held-to-Maturity, Amortized Cost	$686,618	$639,631
Held-to-Maturity, Gross Unrealized Gains	24,979	25,404
Held-to-Maturity, Gross Unrealized Losses	-333	-664
Held-to-Maturity, Fair Value	711,264	664,371
States and Political Subdivisions [Member]
Investment [Line Items]
Held-to-Maturity, Amortized Cost	417,361	385,623
Held-to-Maturity, Gross Unrealized Gains	19,559	20,100
Held-to-Maturity, Gross Unrealized Losses	-46	-58
Held-to-Maturity, Fair Value	436,874	405,665
Corporate Bonds [Member]
Investment [Line Items]
Held-to-Maturity, Amortized Cost	191,594	176,880
Held-to-Maturity, Gross Unrealized Gains	812	374
Held-to-Maturity, Gross Unrealized Losses	-207	-520
Held-to-Maturity, Fair Value	192,199	176,734
Commercial Mortgage-Backed Securities [Member]
Investment [Line Items]
Held-to-Maturity, Amortized Cost	46,094	46,662
Held-to-Maturity, Gross Unrealized Gains	1,495	1,867
Held-to-Maturity, Fair Value	47,589	48,529
U.S. Agency-Based Mortgage-Backed Securities [Member]
Investment [Line Items]
Held-to-Maturity, Amortized Cost	15,953	16,972
Held-to-Maturity, Gross Unrealized Gains	1,691	1,702
Held-to-Maturity, Gross Unrealized Losses	-2	-2
Held-to-Maturity, Fair Value	17,642	18,672
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Investment [Line Items]
Held-to-Maturity, Amortized Cost	12,932	10,697
Held-to-Maturity, Gross Unrealized Gains	1,176	1,097
Held-to-Maturity, Gross Unrealized Losses		-2
Held-to-Maturity, Fair Value	14,108	11,792
Asset-Backed Securities [Member]
Investment [Line Items]
Held-to-Maturity, Amortized Cost	2,684	2,797
Held-to-Maturity, Gross Unrealized Gains	246	264
Held-to-Maturity, Gross Unrealized Losses	-78	-82
Held-to-Maturity, Fair Value	$2,852	$2,979

Investments_Gross_Unrealized_G1

Investments - Gross Unrealized Gains and Losses and Cost or Amortized Cost and Fair Value of Investments Classified as Available-for-Sale (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment [Line Items]
Available-for-Sale, Cost or Amortized Cost	$367,319	$337,004
Available-for-Sale, Gross Unrealized Gains	10,421	9,508
Available-for-Sale, Gross Unrealized Losses	-3,179	-3,494
Available-for-Sale, Fair Value	374,561	343,018
Total Fixed Maturity [Member]
Investment [Line Items]
Available-for-Sale, Cost or Amortized Cost	357,319	327,004
Available-for-Sale, Gross Unrealized Gains	8,664	7,732
Available-for-Sale, Gross Unrealized Losses	-3,179	-3,494
Available-for-Sale, Fair Value	362,804	331,242
Other Investments [Member]
Investment [Line Items]
Available-for-Sale, Cost or Amortized Cost	10,000	10,000
Available-for-Sale, Gross Unrealized Gains	1,729	1,748
Available-for-Sale, Fair Value	11,729	11,748
States and Political Subdivisions [Member]
Investment [Line Items]
Available-for-Sale, Cost or Amortized Cost	168,277	151,744
Available-for-Sale, Gross Unrealized Gains	7,634	7,302
Available-for-Sale, Gross Unrealized Losses	-2,189	-1,672
Available-for-Sale, Fair Value	173,722	157,374
Corporate Bonds [Member]
Investment [Line Items]
Available-for-Sale, Cost or Amortized Cost	179,275	165,412
Available-for-Sale, Gross Unrealized Gains	1,026	428
Available-for-Sale, Gross Unrealized Losses	-154	-470
Available-for-Sale, Fair Value	180,147	165,370
U.S. Agency-Based Mortgage-Backed Securities [Member]
Investment [Line Items]
Available-for-Sale, Cost or Amortized Cost	9,767	9,848
Available-for-Sale, Gross Unrealized Gains	4	2
Available-for-Sale, Gross Unrealized Losses	-836	-1,352
Available-for-Sale, Fair Value	8,935	8,498
Equity Securities [Member]
Investment [Line Items]
Available-for-Sale, Gross Unrealized Gains	28	28
Available-for-Sale, Fair Value	$28	$28

Investments_Summary_of_Amortiz

Investments - Summary of Amortized Cost and Fair Value of Investments in Fixed Maturity Securities, Classified as Held-to-Maturity (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment [Line Items]
Within one year, Amortized Cost	$142,860
After one year through five years, Amortized Cost	282,666
After five years through ten years, Amortized Cost	114,203
After ten years, Amortized Cost	82,158
Held-to-Maturity, Amortized Cost	686,618	639,631
Within one year, Fair Value	143,563
After one year through five years, Fair Value	292,645
After five years through ten years, Fair Value	121,383
After ten years, Fair Value	85,590
Total, Fair Value	711,264	664,371
U.S. Agency-Based Mortgage-Backed Securities [Member]
Investment [Line Items]
Held-to-maturity, Amortized Cost	15,953
Held-to-maturity, Fair Value	17,642
Commercial Mortgage-Backed Securities [Member]
Investment [Line Items]
Held-to-maturity, Amortized Cost	46,094
Held-to-maturity, Fair Value	47,589
Asset-Backed Securities [Member]
Investment [Line Items]
Held-to-maturity, Amortized Cost	2,684
Held-to-maturity, Fair Value	$2,852

Investments_Summary_of_Amortiz1

Investments - Summary of Amortized Cost and Fair Value of Investments in Fixed Maturity Securities, Classified as Available-for-Sale (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment [Line Items]
Due in 2015, Amortized Cost	$54,548
In 2016 through 2019, Amortized Cost	145,418
In 2020 through 2024, Amortized Cost	17,163
After 2024, Amortized Cost	130,423
Total , Amortized Cost	357,319	327,004
Due in 2015, Fair Value	54,603
In 2016 through 2019, Fair Value	146,672
In 2020 through 2024, Fair Value	17,429
After 2024, Fair Value	135,165
Total, Fair Value	362,804	331,242
U.S. Agency-Based Mortgage-Backed Securities [Member]
Investment [Line Items]
Available-for-sale securities, Amortized Cost	9,767
Available-for-sale securities, Fair value	$8,935

Investments_Investment_Securit

Investments - Investment Securities Continuous Unrealized Loss Position (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$95,065	$150,147
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Accumulated Loss	248	582
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	5,893	1,662
Held-to-maturity Securities, Continuous Unrealized Loss Position Twelve Months Or Longer, Accumulated Loss	85	82
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	100,958	151,809
Held-to-maturity Securities, Gross Unrealized Losses	333	664
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	56,967	110,622
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	172	487
Available-for Sale Fair, Value of Investments with Unrealized Losses, 12 Months or Greater	19,743	18,104
Available-for Sale, Gross Unrealized Losses, 12 Months or Greater	3,007	3,007
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	76,710	128,726
Available-for Sale, Gross Unrealized Losses, Total	3,179	3,494
Fair Value of Investments with Unrealized Losses, Less Than 12 months	152,032	260,769
Gross Unrealized Loss, Less Than 12 Months	420	1,069
Fair Value of Investments with Unrealized Losses, 12 Months or Greater	25,636	19,766
Gross Unrealized Losses, 12 Months or Greater	3,092	3,089
Fair Value of Investments with Unrealized Losses, Total	177,668	280,535
Gross Unrealized Losses, Total	3,512	4,158
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Investment [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		3,385
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Accumulated Loss		2
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value		3,385
Held-to-maturity Securities, Gross Unrealized Losses		2
Corporate Bonds [Member]
Investment [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	76,863	129,788
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Accumulated Loss	200	520
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	4,280
Held-to-maturity Securities, Continuous Unrealized Loss Position Twelve Months Or Longer, Accumulated Loss	7
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	81,143	129,788
Held-to-maturity Securities, Gross Unrealized Losses	207	520
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	52,767	106,185
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	150	470
Available-for Sale Fair, Value of Investments with Unrealized Losses, 12 Months or Greater	1,028
Available-for Sale, Gross Unrealized Losses, 12 Months or Greater	4
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	53,795	106,185
Available-for Sale, Gross Unrealized Losses, Total	154	470
States and Political Subdivisions [Member]
Investment [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	18,113	16,896
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Accumulated Loss	46	58
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	18,113	16,896
Held-to-maturity Securities, Gross Unrealized Losses	46	58
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	4,200	3,810
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	22	6
Available-for Sale Fair, Value of Investments with Unrealized Losses, 12 Months or Greater	9,888	10,347
Available-for Sale, Gross Unrealized Losses, 12 Months or Greater	2,167	1,666
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	14,088	14,157
Available-for Sale, Gross Unrealized Losses, Total	2,189	1,672
U.S. Agency-Based Mortgage-Backed Securities [Member]
Investment [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	89	78
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Accumulated Loss	2	2
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	89	78
Held-to-maturity Securities, Gross Unrealized Losses	2	2
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months		627
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months		11
Available-for Sale Fair, Value of Investments with Unrealized Losses, 12 Months or Greater	8,827	7,757
Available-for Sale, Gross Unrealized Losses, 12 Months or Greater	836	1,341
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	8,827	8,384
Available-for Sale, Gross Unrealized Losses, Total	836	1,352
Asset-Backed Securities [Member]
Investment [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,613	1,662
Held-to-maturity Securities, Continuous Unrealized Loss Position Twelve Months Or Longer, Accumulated Loss	78	82
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	1,613	1,662
Held-to-maturity Securities, Gross Unrealized Losses	$78	$82

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
	Individual
Investments Schedule [Abstract]
Individual fixed maturity held in unrealized loss position	112
Individual fixed maturity held in unrealized loss position longer than 12 months	22
Carrying value of investments	$11,700,000
Net realized gains on investments	$59,000	$101,000

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$0
Company recognized uncertain tax positions	$0	$0

Comprehensive_Income_and_Accum2

Comprehensive Income and Accumulated Other Comprehensive Income - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Comprehensive income	$15,948	$13,789
Comprehensive income tax rate	35.00%

Comprehensive_Income_and_Accum3

Comprehensive Income and Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (AOCI) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	$2,810	($4,295)
Other comprehensive income before reclassification	883	3,134
Amounts reclassified from accumulated other comprehensive income	-65	106
Net current period other comprehensive income	818	3,240
Ending balance	$3,628	($1,055)

Comprehensive_Income_and_Accum4

Comprehensive Income and Accumulated Other Comprehensive Income - Reclassification Out of Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$21,197	$13,404
Income tax expense	-6,067	-2,855
Net income	15,130	10,549
Changes in Net Unrealized Gains (Losses) on Investment Securities [Member] | Reclassification Out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains/losses on available-for-sale securities	100	-163
Income before income taxes	100	-163
Income tax expense	-35	57
Net income	$65	($106)

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	$374,561	$343,018
Equity Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	28	28
Other Investments [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	11,729	11,748
Fair Value, Measurements, Recurring [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	374,561	343,018
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	362,804	331,242
Fair Value, Measurements, Recurring [Member] | Other Investments [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	11,729	11,748
Fair Value, Measurements, Recurring [Member] | Common Stock [Member] | Equity Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	28	28
Fair Value, Measurements, Recurring [Member] | States and Political Subdivisions [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	173,722	157,374
Fair Value, Measurements, Recurring [Member] | U.S. Agency-Based Mortgage-Backed Securities [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	8,935	8,498
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	180,147	165,370
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	28	28
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Common Stock [Member] | Equity Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	28	28
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	362,804	331,242
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	362,804	331,242
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | States and Political Subdivisions [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	173,722	157,374
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Agency-Based Mortgage-Backed Securities [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	8,935	8,498
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member] | Debt Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	180,147	165,370
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	11,729	11,748
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Other Investments [Member]
Fair Value Measurements Disclosure [Line Items]
Securities available for sale/Available-for-sale, Fair value	$11,729	$11,748

Fair_Value_Measurements_Schedu1

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Amortized Cost (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	$711,264	$664,371
States and Political Subdivisions [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	436,874	405,665
Corporate Bonds [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	192,199	176,734
Commercial Mortgage-Backed Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	47,589	48,529
U.S. Agency-Based Mortgage-Backed Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	17,642	18,672
US Treasury Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	14,108	11,792
Asset-Backed Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	2,852	2,979
Fair Value, Inputs, Level 1 [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	14,108	11,792
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	14,108	11,792
Fair Value, Inputs, Level 2 [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	697,156	652,579
Fair Value, Inputs, Level 2 [Member] | States and Political Subdivisions [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	436,874	405,665
Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	192,199	176,734
Fair Value, Inputs, Level 2 [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	47,589	48,529
Fair Value, Inputs, Level 2 [Member] | U.S. Agency-Based Mortgage-Backed Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	17,642	18,672
Fair Value, Inputs, Level 2 [Member] | Asset-Backed Securities [Member]
Fair Value Measurements Disclosure [Line Items]
Securities held-to-maturity-fixed maturity, Fair Value	$2,852	$2,979

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Carrying Values and Corresponding Fair Values for Financial Instruments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturity securities-held-to-maturity	$711,264	$664,371
Fixed maturity securities-held-to-maturity	686,618	639,631
Fixed maturity securities-available-for-sale	362,804	331,242
Equity securities	28	28
Short-term investments	12,184	33,684
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturity securities-held-to-maturity	686,618	639,631
Fixed maturity securities-available-for-sale	362,804	331,242
Equity securities	28	28
Cash and cash equivalents	79,731	90,956
Short-term investments	12,184	33,684
Other investments	11,729	11,748
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturity securities-held-to-maturity	711,264	664,371
Fixed maturity securities-available-for-sale	362,804	331,242
Equity securities	28	28
Cash and cash equivalents	79,731	90,956
Short-term investments	12,184	33,684
Other investments	$11,729	$11,748

Fair_Value_Measurements_Summar1

Fair Value Measurements - Summary of Changes in Fair Value of Assets Measured at Fair Value (Detail) (Fair Value, Inputs, Level 3 [Member], USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements Disclosure [Line Items]
Beginning balance	$11,748	$10,591
Total unrealized gains/(losses)	-19	1,157
Ending balance	$11,729	$11,748

Treasury_Stock_Additional_Info

Treasury Stock - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2011
Equity [Abstract]
Share repurchase new limit amount			$25,000,000	$25,000,000	$25,000,000	$25,000,000
Share repurchase program expiration date	31-Dec-15
Shares repurchased	1,258,250	1,258,250
Shares repurchased, value	$22,400,000
Shares repurchased, average price	$17.78

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (Dividend Declared [Member], USD $)	3 Months Ended
	Mar. 31, 2015	Apr. 28, 2015
Subsequent Event [Line Items]
Date of payment to shareholders entitled to dividends	26-Jun-15
Date of record of shareholders entitled to dividends	12-Jun-15
Subsequent Event [Member]
Subsequent Event [Line Items]
Cash dividend per share		$0.15