ProAssurance (PRA) 10-K 20 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 12, 2014	Jun. 30, 2013
Document and Entity Information [Abstract]	'	'	'
Entity Registrant Name	'PROASSURANCE CORP	'	'
Entity Central Index Key	'0001127703	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Amendment Flag	'false	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	60,486,816	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$3,178,444,502

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investments	'	'
Fixed maturities, available for sale, at fair value; amortized cost, $3,026,256 and $3,224,332, respectively	$3,118,049	$3,447,999
Equity securities, trading, at fair value; cost, $203,308 and $187,891, respectively	253,541	202,618
Short-term investments	248,605	71,737
Business owned life insurance	54,374	52,414
Investment in unconsolidated subsidiaries	214,236	121,049
Other investments	52,240	31,085
Total Investments	3,941,045	3,926,902
Cash and cash equivalents	129,383	118,551
Restricted Cash	78,000	0
Premiums receivable	115,403	106,312
Receivable from reinsurers on paid losses and loss adjustment expenses	3,231	4,517
Receivable from reinsurers on unpaid losses and loss adjustment expenses	247,518	191,645
Prepaid reinsurance premiums	21,449	13,404
Deferred policy acquisition costs	28,999	23,179
Deferred tax asset	1,757	0
Real estate, net	41,010	41,502
Intangible assets	52,002	53,225
Goodwill	161,115	163,055
Other assets	329,979	234,286
Total Assets	5,150,891	4,876,578
Policy liabilities and accruals	'	'
Reserve for losses and loss adjustment expenses	2,072,822	2,054,994
Unearned premiums	256,255	233,861
Reinsurance premiums payable	34,321	45,591
Total Policy Liabilities	2,363,398	2,334,446
Deferred tax liability	0	14,585
Other liabilities	143,079	131,967
Long-term debt, at amortized cost	250,000	125,000
Total Liabilities	2,756,477	2,605,998
Shareholders’ Equity:	'	'
Common shares, par value $0.01 per share, 100,000,000 shares authorized, 62,096,787 and 61,867,034 shares issued, respectively	621	619
Additional paid-in capital	349,894	341,780
Accumulated other comprehensive income (loss), net of deferred tax expense (benefit) of $32,127 and $78,284, respectively	59,661	145,380
Retained earnings	2,015,603	1,782,857
Total Shareholders' Equity Before Treasury Shares	2,425,779	2,270,636
Treasury shares, at cost, 900,281 shares and 243,530 shares, respectively	-31,365	-56
Total Shareholders’ Equity	2,394,414	2,270,580
Total Liabilities and Shareholders’ Equity	$5,150,891	$4,876,578

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Fixed maturities, available for sale, at fair value; amortized cost	$3,026,256	$3,224,332
Equity securities, trading, cost	203,308	187,891
Common shares, par value (USD per share)	$0.01	$0.01
Common shares, shares authorized	100,000,000	100,000,000
Common shares, shares issued	62,096,787	61,867,034
Deferred tax expense (benefit) on accumulated other comprehensive income (loss)	$32,127	$78,284
Treasury shares, number of shares	900,281	243,530

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Capital (USD $)	3 Months Ended				12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Increase (Decrease) in Stockholders' Equity:	'	'	'	'	'	'	'
Beginning Balance	'	$2,270,580	'	$2,164,453	$2,270,580	$2,164,453	$1,855,863
Common shares reacquired	'	'	'	'	-32,454	'	-21,005
Common shares issued for compensation and effect of shares reissued to stock purchase plan	'	'	'	'	4,085	3,594	2,874
Share-based compensation	'	'	'	'	9,242	8,639	7,119
Net effect of restricted and performance shares issued and stock options exercised	'	'	'	'	-4,066	-4,453	-3,138
Dividends to shareholders	'	'	'	'	-64,777	-192,466	-15,269
Two-for-one stock split effected in the form of a stock dividend	'	'	'	'	'	0	'
Other comprehensive income (loss)	'	'	'	'	-85,719	15,343	50,913
Net income	70,864	112,850	101,266	55,645	297,523	275,470	287,096
Ending Balance	2,394,414	'	2,270,580	'	2,394,414	2,270,580	2,164,453
Common Stock	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity:	'	'	'	'	'	'	'
Beginning Balance	'	619	'	346	619	346	344
Common shares reacquired	'	'	'	'	0	'	0
Common shares issued for compensation and effect of shares reissued to stock purchase plan	'	'	'	'	0	0	0
Share-based compensation	'	'	'	'	0	0	0
Net effect of restricted and performance shares issued and stock options exercised	'	'	'	'	2	2	2
Dividends to shareholders	'	'	'	'	0	0	0
Two-for-one stock split effected in the form of a stock dividend	'	'	'	'	'	271	'
Other comprehensive income (loss)	'	'	'	'	0	0	0
Net income	'	'	'	'	0	0	0
Ending Balance	621	'	619	'	621	619	346
Additional Paid-in Capital	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity:	'	'	'	'	'	'	'
Beginning Balance	'	341,780	'	538,625	341,780	538,625	532,213
Common shares reacquired	'	'	'	'	0	'	0
Common shares issued for compensation and effect of shares reissued to stock purchase plan	'	'	'	'	2,940	3,041	2,433
Share-based compensation	'	'	'	'	9,242	8,639	7,119
Net effect of restricted and performance shares issued and stock options exercised	'	'	'	'	-4,068	-4,455	-3,140
Dividends to shareholders	'	'	'	'	0	0	0
Two-for-one stock split effected in the form of a stock dividend	'	'	'	'	'	-204,070	'
Other comprehensive income (loss)	'	'	'	'	0	0	0
Net income	'	'	'	'	0	0	0
Ending Balance	349,894	'	341,780	'	349,894	341,780	538,625
Accumulated Other Comprehensive Income (Loss)	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity:	'	'	'	'	'	'	'
Beginning Balance	'	145,380	'	130,037	145,380	130,037	79,124
Common shares reacquired	'	'	'	'	0	'	0
Common shares issued for compensation and effect of shares reissued to stock purchase plan	'	'	'	'	0	0	0
Share-based compensation	'	'	'	'	0	0	0
Net effect of restricted and performance shares issued and stock options exercised	'	'	'	'	0	0	0
Dividends to shareholders	'	'	'	'	0	0	0
Two-for-one stock split effected in the form of a stock dividend	'	'	'	'	'	0	'
Other comprehensive income (loss)	'	'	'	'	-85,719	15,343	50,913
Net income	'	'	'	'	0	0	0
Ending Balance	59,661	'	145,380	'	59,661	145,380	130,037
Retained Earnings	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity:	'	'	'	'	'	'	'
Beginning Balance	'	1,782,857	'	1,699,853	1,782,857	1,699,853	1,428,026
Common shares reacquired	'	'	'	'	0	'	0
Common shares issued for compensation and effect of shares reissued to stock purchase plan	'	'	'	'	0	0	0
Share-based compensation	'	'	'	'	0	0	0
Net effect of restricted and performance shares issued and stock options exercised	'	'	'	'	0	0	0
Dividends to shareholders	'	'	'	'	-64,777	-192,466	-15,269
Two-for-one stock split effected in the form of a stock dividend	'	'	'	'	'	0	'
Other comprehensive income (loss)	'	'	'	'	0	0	0
Net income	'	'	'	'	297,523	275,470	287,096
Ending Balance	2,015,603	'	1,782,857	'	2,015,603	1,782,857	1,699,853
Treasury Stock	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity:	'	'	'	'	'	'	'
Beginning Balance	'	-56	'	-204,408	-56	-204,408	-183,844
Common shares reacquired	'	'	'	'	-32,454	'	-21,005
Common shares issued for compensation and effect of shares reissued to stock purchase plan	'	'	'	'	1,145	553	441
Share-based compensation	'	'	'	'	0	0	0
Net effect of restricted and performance shares issued and stock options exercised	'	'	'	'	0	0	0
Dividends to shareholders	'	'	'	'	0	0	0
Two-for-one stock split effected in the form of a stock dividend	'	'	'	'	'	203,799	'
Other comprehensive income (loss)	'	'	'	'	0	0	0
Net income	'	'	'	'	0	0	0
Ending Balance	($31,365)	'	($56)	'	($31,365)	($56)	($204,408)

Consolidated_Statements_of_Inc

Consolidated Statements of Income and Comprehensive Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'
Net premiums earned	$527,919	$550,664	$565,415
Net investment income	129,265	136,094	140,956
Equity in earnings (loss) of unconsolidated subsidiaries	7,539	-6,873	-9,147
Net realized investment gains (losses):	'	'	'
Other-than-temporary impairment (OTTI) losses	-71	-1,566	-5,189
Portion of OTTI losses recognized in (reclassified from) other comprehensive income before taxes	0	-201	-823
Net impairment losses recognized in earnings	-71	-1,767	-6,012
Other net realized investment gains (losses)	67,975	30,630	12,006
Total net realized investment gains (losses)	67,904	28,863	5,994
Other income	7,551	7,106	13,566
Total revenues	740,178	715,854	716,784
Expenses	'	'	'
Losses and loss adjustment expenses	243,015	161,726	151,270
Reinsurance recoveries	-18,254	18,187	11,017
Net losses and loss adjustment expenses	224,761	179,913	162,287
Underwriting, policy acquisition and operating expenses	147,817	135,631	136,421
Interest expense	2,755	2,181	3,478
Loss on extinguishment of debt	0	2,163	0
Total expenses	375,333	319,888	302,186
Gain on acquisition	32,314	0	0
Income before income taxes	397,159	395,966	414,598
Provision for income taxes	'	'	'
Current expense (benefit)	74,977	82,752	128,553
Deferred expense (benefit)	24,659	37,744	-1,051
Total income tax expense (benefit)	99,636	120,496	127,502
Net income	297,523	275,470	287,096
Other comprehensive income (loss), after tax, net of reclassification adjustments	-85,719	15,343	50,913
Comprehensive income	$211,804	$290,813	$338,009
Earnings per share:	'	'	'
Basic (USD per share)	$4.82	$4.49	$4.70
Diluted (USD per share)	$4.80	$4.46	$4.65
Weighted average number of common shares outstanding:	'	'	'
Basic (in shares)	61,761	61,342	61,140
Diluted (in shares)	62,020	61,833	61,684
Cash dividends declared per common share	$1.05	$3.13	$0.25

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Activities	'	'	'
Net income	$297,523	$275,470	$287,096
Amortization, net of accretion	41,429	32,832	30,740
Depreciation	4,538	4,741	4,949
Loss (gain) on extinguishment of debt	0	-2,163	0
Gain on acquisition	-32,314	0	0
(Increase) decrease in cash surrender value of business owned life insurance	-1,960	-2,008	-2,070
Net realized investment gains	-67,904	-28,863	-5,994
Share-based compensation	9,242	8,639	7,119
Deferred income taxes	24,659	37,744	-1,051
Policy acquisition costs, net amortization (net deferral)	-5,820	3,448	655
Equity in earnings of unconsolidated subsidiaries, excluding distributions received and tax credit partnership amortization	-17,376	450	3,757
Other	-3,014	-2,957	-866
Other changes in assets and liabilities, excluding effect of business combinations:	'	'	'
Premiums receivable	-6,105	16,494	730
Receivable from reinsurers on paid losses and loss adjustment expenses	2,601	-342	407
Receivable from reinsurers on unpaid losses and loss adjustment expenses	15,625	58,870	29,778
Prepaid reinsurance premiums	-849	-482	-1,545
Other assets	9,582	-11,231	613
Reserve for losses and loss adjustment expenses	-179,677	-218,100	-166,328
Unearned premiums	-1,740	-21,919	-4,895
Reinsurance premiums payable	-13,269	-36,583	-29,642
Other liabilities	-36,569	-27,116	5,911
Net cash provided (used) by operating activities	38,602	91,250	159,364
Purchases of:	'	'	'
Fixed maturities, available for sale	-519,161	-646,198	-782,555
Equity securities, trading	-87,604	-120,555	-117,208
Other investments	-34,699	-9,977	-4,671
Funding of tax credit limited partnerships	-63,489	-35,745	-29,213
(Investment in) distributions from unconsolidated subsidiaries, net	-3,261	-9,621	0
Proceeds from sales or maturities of:	'	'	'
Fixed maturities, available for sale	970,708	926,221	789,709
Equity securities, available for sale	0	0	3,921
Equity securities, trading	123,645	54,670	50,386
Other investments	2,352	1,180	773
Net sales or maturities (purchases) of short-term investments	-176,092	48,565	49,011
Cash received from (paid for) acquisitions	22,780	-28,439	0
Deposit made for future acquisition	-205,244	-153,700	0
Unsettled security transactions, net	205	4,852	7
Funding for Syndicate 1729	-8,699	0	0
Cash received (paid) for other assets	-11,244	-4,410	-9,771
(Increase) decrease in restricted cash	-78,000	0	0
Net cash provided (used) by investing activities	-67,803	26,843	-49,611
Financing Activities	'	'	'
Proceeds from long-term debt	250,000	125,000	0
Repayment of long-term debt	-127,183	-57,660	-325
Repurchase of common stock	-29,089	0	-21,005
Excess tax benefit from share-based payment arrangements	2,128	7,022	1,711
Dividends to shareholders	-46,375	-200,118	-7,617
Other	-9,448	-4,186	-2,968
Net cash provided (used) by financing activities	40,033	-129,942	-30,204
Increase (decrease) in cash and cash equivalents	10,832	-11,849	79,549
Cash and cash equivalents at beginning of period	118,551	130,400	50,851
Cash and cash equivalents at end of period	129,383	118,551	130,400
Supplemental Disclosure of Cash Flow Information	'	'	'
Net cash paid during the year for income taxes	117,107	110,278	98,141
Cash paid during the year for interest	913	2,342	3,182
Significant non-cash transactions	'	'	'
Deposit transferred as consideration for acquisition	153,700	0	0
Other investment interest converted to equity securities	0	15,742	0
Parent Company [Member]	'	'	'
Operating Activities	'	'	'
Net income	297,523	275,470	287,096
Other changes in assets and liabilities, excluding effect of business combinations:	'	'	'
Net cash provided (used) by operating activities	-26,319	3,601	-3,982
Purchases of:	'	'	'
Equity securities, trading	-1,265	-364	-990
Proceeds from sales or maturities of:	'	'	'
Fixed maturities, available for sale	224,993	150,192	19,398
Equity securities, trading	1,113	616	6,887
Net sales or maturities (purchases) of short-term investments	-187,625	58,657	-28,708
Funding for Syndicate 1729	-8,699	0	0
Cash received (paid) for other assets	-20	-1	-3,070
(Increase) decrease in restricted cash	-78,000	0	0
Net cash provided (used) by investing activities	-15,263	84,139	71,037
Financing Activities	'	'	'
Proceeds from long-term debt	250,000	125,000	0
Repayment of long-term debt	-125,000	-32,992	0
Repurchase of common stock	-29,089	0	-21,005
Excess tax benefit from share-based payment arrangements	2,128	7,022	1,711
Dividends to shareholders	-46,375	-200,118	-7,617
Other	-8,278	-12,259	-2,561
Net cash provided (used) by financing activities	49,644	-106,281	-23,401
Increase (decrease) in cash and cash equivalents	8,062	-18,541	43,654
Cash and cash equivalents at beginning of period	29,397	47,938	4,284
Cash and cash equivalents at end of period	$37,459	$29,397	$47,938

Accounting_Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Accounting Policies	'
	Accounting Policies
	Organization and Nature of Business
	ProAssurance Corporation (ProAssurance, PRA or the Company), a Delaware corporation, is an insurance holding company for wholly owned specialty property and casualty insurance companies that principally provide professional liability insurance for healthcare professionals and facilities, professional liability insurance for attorneys, liability insurance for medical technology and life sciences risks and, effective January 1, 2014, workers' compensation insurance. ProAssurance is also the majority capital provider for Syndicate 1729 at Lloyd's of London (Syndicate 1729) which began writing a range of property and casualty insurance and reinsurance lines effective January 1, 2014. During the years ended December 31, 2013, 2012 and 2011 ProAssurance primarily operated in the United States of America (U.S.) in a single reportable segment.
	Principles of Consolidation
	The accompanying consolidated financial statements include the accounts of ProAssurance Corporation and its wholly-owned subsidiaries. Investments in entities where ProAssurance holds a greater than minor interest but does not hold a controlling interest are accounted for using the equity method. All significant intercompany accounts and transactions are eliminated in consolidation.
	Basis of Presentation
	The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and disclosures related to these amounts at the date of the financial statements. Actual results could differ from those estimates.
	Stock Split
	In 2012, the Board of Directors of ProAssurance Corporation (the Board) declared a two-for-one split of ProAssurance common shares which was effected December 27, 2012 in the form of a stock dividend. All share and per share information provided in this report reflects the effect of the split for all periods presented.
	Gain on Acquisition
	The year-end deferred tax review resulted in a $3.7 million reduction of the Gain on acquisition recorded for our acquisition of Medmarc. Certain deferred tax liabilities relating to unrealized gains on investments held by Medmarc were not established as a part of the assets acquired and liabilities assumed for Medmarc and as a result the value of the net assets acquired in the transaction were overstated. An adjustment was made to the Gain on acquisition in the fourth quarter of 2013 reducing the gain from $36.0 million to $32.3 million. The adjustment was not quantitatively or qualitatively material to the prior or current period presented.
	Accounting Policies
	The significant accounting policies followed by ProAssurance in making estimates that materially affect financial reporting are summarized in these notes to the consolidated financial statements.
	Recognition of Revenues
	Insurance premiums are recognized as revenues pro rata over the terms of the policies, which are principally one year in duration.
	At December 31, 2013 and 2012 ProAssurance had established allowances for credit losses related to premium and agency receivables (classified as a part of Other Assets) as follows:
	(in thousands)		Premium			Agency
			Receivables			Receivables
	Allowance for credit losses:
	Balance at December 31, 2011		$	990		$	332
	Estimated credit losses		157			—
	Account write offs, net of recoveries		(147		)	(46		)
	Balance at December 31, 2012		1,000			286
	Estimated credit losses		236			—
	Account write offs, net of recoveries		(246		)	(236		)
	Balance at December 31, 2013		$	990		$	50
	Losses and Loss Adjustment Expenses
	ProAssurance establishes its reserve for losses and loss adjustment expenses ("reserve for losses" or "reserve") based on estimates of the future amounts necessary to pay claims and expenses associated with the investigation and settlement of claims. The reserve for losses is determined on the basis of individual claims and payments thereon as well as actuarially determined estimates of future losses based on past loss experience, available industry data and projections as to future claims frequency, severity, inflationary trends, judicial trends, legislative changes and settlement patterns.
	Management establishes the reserve for losses after taking into consideration a variety of factors including the conclusions reached by internal actuaries, premium rates, claims frequency, historical paid and incurred loss development trends, the effect of inflation, general economic trends, the legal and political environment, and the reports received from consulting actuaries. Internal actuaries perform an in-depth review of the reserve for losses at least semi-annually using the loss and exposure data of ProAssurance subsidiaries. Management engages consulting actuaries to review subsidiary loss and exposure data and provide reports to Management regarding the adequacy of reserves.
	Estimating casualty insurance reserves, and particularly long-tailed insurance reserves, is a complex process. Long-tailed insurance is characterized by the extended period of time between collecting the premium for insuring a risk and the ultimate payment of losses. For ProAssurance the period of time required to resolve claims is often five years or more, and claims may be subject to litigation. Estimating losses for long-tailed insurance claims requires ProAssurance to make and revise judgments and assessments regarding multiple uncertainties over an extended period of time. As a result, reserve estimates may vary significantly from the eventual outcome. Reserve estimates and the assumptions on which these estimates are predicated are regularly reviewed and updated as new information becomes available. Any adjustments necessary are reflected in then current operations. Due to the size of ProAssurance’s reserve for losses, even a small percentage adjustment to these estimates could have a material effect on earnings in the period in which the adjustment is made, as was the case in 2013, 2012 and 2011.
	The effect of adjustments made to reinsured losses is mitigated by the corresponding adjustment that is made to reinsurance recoveries. Thus, in any given year, ProAssurance may make significant adjustments to gross losses that have little effect on its net losses.
	Reinsurance Receivables
	ProAssurance enters into reinsurance agreements whereby other insurance entities agree to assume a portion of the risk associated with the policies issued by ProAssurance. In return, ProAssurance agrees to pay a premium to the reinsurer. ProAssurance purchases reinsurance to provide for greater diversification of business and to allow management to control exposure to potential losses arising from large risks.
	Receivable from Reinsurers on Paid Losses is the estimated amount of losses already paid that will be recoverable from reinsurers. Receivable from Reinsurers on Unpaid Losses is the estimated amount of future loss payments that will be recoverable from reinsurers. Reinsurance Recoveries are the portion of losses incurred during the period that are estimated to be allocable to reinsurers. Premiums ceded are the estimated premiums that will be due to reinsurers with respect to premiums earned and losses incurred during the period.
	These estimates are based upon management’s estimates of ultimate losses and the portion of those losses that are allocable to reinsurers under the terms of the related reinsurance agreements. Given the uncertainty of the ultimate amounts of losses, these estimates may vary significantly from the eventual outcome. Management regularly reviews these estimates and any adjustments necessary are reflected in the period in which the estimate is changed. Due to the size of the receivable from reinsurers, even a small adjustment to the estimates could have a material effect on ProAssurance’s results of operations for the period in which the change is made.
	Reinsurance contracts do not relieve ProAssurance from its obligations to policyholders. ProAssurance continually monitors its reinsurers to minimize its exposure to significant losses from reinsurer insolvencies. Any amount determined to be uncollectible is written off in the period in which the uncollectible amount is identified.
	Investments
	Fair Values
	Fair values of investment securities are primarily provided by independent pricing services. The pricing services provide an exchange traded price, if available, or provide an estimated price determined using multiple observable inputs, including exchange traded prices for similar assets. Management reviews valuations of securities obtained from the pricing services for accuracy based upon the specifics of the security, including class, maturity, credit rating, durations, collateral, and comparable markets for similar securities. Multiple observable inputs are not available for certain of our investments, including municipal bonds and corporate debt not actively traded, and investments in limited partnerships/limited liability companies (LPs/LLCs). Management values these municipal bonds and corporate debt either using a single non-binding broker quote or pricing models that utilize market based assumptions that have limited observable inputs. Management values investments in LPs/LLCs based on the net asset value of the interest held, as provided by the fund.
	Fixed Maturities and Equity Securities
	Fixed maturities and equity securities are considered as either available-for-sale or trading securities.
	Available-for-sale securities are carried at fair value, determined as described above, and unrealized gains and losses on such available-for-sale securities are included, net of related tax effects, in Shareholders’ Equity as a component of Accumulated Other Comprehensive Income (Loss).
	Investment income includes amortization of premium and accretion of discount related to available-for-sale debt securities acquired at other than par value. Debt securities and mandatorily redeemable preferred stock with maturities beyond one year when purchased are classified as fixed maturities.
	Trading portfolio securities are carried at fair value, determined as described above, with the holding gains and losses included in realized investment gains and losses in the current period.
	Short-term Investments
	Short-term investments, which have a maturity at purchase of one year or less, are primarily comprised of investments in U.S. Treasury obligations and commercial paper. All balances are reported at amortized cost, which approximates fair value.
	Other Investments
	Investments in LPs/LLCs where ProAssurance has virtually no influence over the operating and financial policies of an investee are accounted for using the cost method. Under the cost method, investments are valued at cost, with investment income recognized when received.
	Investment in Unconsolidated Subsidiaries
	Investments in LPs/LLCs where ProAssurance is deemed to have influence because it holds a greater than a minor interest are accounted for using the equity method. Under the equity method, the recorded basis of the investment is adjusted each period for the investor’s pro rata share of the investee’s income or loss. Investments in unconsolidated subsidiaries include tax credit partnerships accounted for using the equity method, whereby ProAssurance’s proportionate share of income or loss is included in investment income. Tax credits received from the partnerships are recognized in the period received as a reduction to current tax expenses.
	Business Owned Life Insurance (BOLI)
	ProAssurance owns life insurance contracts on certain management employees. The life insurance contracts are carried at their current cash surrender value. Changes in the cash surrender value are included in income in the current period as investment income. Death proceeds from the contracts are recorded when the proceeds become payable under the policy terms.
	Realized Gains and Losses
	Realized investment gains and losses are recognized on the specific identification basis.
	Other-than-temporary Impairments
	ProAssurance evaluates its available-for-sale investment securities on at least a quarterly basis for the purpose of determining whether declines in fair value below recorded cost basis represent other-than-temporary declines. The assessment of whether the amortized cost basis of debt securities, particularly asset-backed debt securities, is expected to be recovered requires management to make assumptions regarding various matters affecting cash flows to be received in the future. The choice of assumptions is subjective and requires the use of judgments; actual credit losses experienced in future periods may differ from management’s estimates of those credit losses.
	If there is intent to sell the security or if it is more likely than not that the security will be required to be sold before full recovery of its amortized cost basis, ProAssurance considers a decline in fair value to be an other-than-temporary impairment. Otherwise, ProAssurance considers the following factors in determining whether an investment’s decline is other-than-temporary:
	For equity securities:
	•	the length of time for which the fair value of the investment has been less than its recorded basis;
	•	the financial condition and near-term prospects of the issuer underlying the investment, taking into consideration the economic prospects of the issuer’s industry and geographical region, to the extent that information is publicly available;
	•	the historical and implied volatility of the fair value of the security;
	For debt securities, an evaluation is made as to whether the decline in fair value is due to credit loss, which is defined as the excess of the current amortized cost basis of the security over the present value of expected future cash flows. Methodologies used to estimate the present value of expected cash flows to determine if a decline is due to a credit loss are:
	•	For non-structured fixed maturities (U.S. Treasury securities, obligations of U.S. Government and government agencies and authorities, obligations of states, municipalities and political subdivisions, and corporate debt) the estimate of expected cash flows is determined by projecting a recovery value and a recovery time frame and assessing whether further principal and interest will be received. ProAssurance considers the following in projecting recovery values and recovery time frames:
•	third party research and credit rating reports;
•	the current credit standing of the issuer, including credit rating downgrades, whether before or after the balance sheet date;
•	internal assessments and the assessments of external portfolio managers regarding specific circumstances surrounding an investment, which indicate the investment is more or less likely to recover its amortized cost than other investments with a similar structure;
•	failure of the issuer of the security to make scheduled interest or principal payments;
•	For structured securities (primarily asset-backed securities), ProAssurance estimates the present value of the security’s cash flows using the effective yield of the security at the date of acquisition (or the most recent implied rate used to accrete the security if the implied rate has changed as a result of a previous impairment or changes in expected cash flows). ProAssurance considers the most recently available six month averages of the levels of delinquencies, defaults, severities, and prepayments for the collateral (loans) underlying the securitization or, if historical data is not available, sector based assumptions, to estimate expected future cash flows of these securities.
Investments in LPs/LLCs are evaluated for impairment by comparing ProAssurance’s carrying value to net asset value (NAV) of ProAssurance’s interest in the fund as reported by the fund manager. Additionally, Management considers the performance of the fund relative to the market, the stated objectives of the fund, and cash flows expected from the fund and fund audit reports, if available.
Investments in tax credit partnerships are evaluated for OTTI by considering both qualitative and quantitative factors which include: whether cash flows currently expected from the investment, primarily tax benefits, equal or exceed the carrying value of the investment, whether currently expected cash flows are less than those expected at the time the investment was acquired, and ProAssurance's ability and intent to hold the investment until the recovery of its carrying value.
ProAssurance recognizes other than temporary impairments, including impairments of debt securities due to credit loss, in earnings as a part of net realized investment gains (losses). In subsequent periods, any measurement of gain or loss or impairment is based on the revised amortized basis of the security. Declines in fair value, including impairments of debt securities that are not evaluated as being due to credit loss, not considered to be other-than-temporary are recognized in other comprehensive income.
Asset-backed securities that have been impaired due to credit or are below investment grade quality are accounted for under the effective yield method. Under the effective yield method estimates of cash flows expected over the life of asset-backed securities are then used to recognize income on the investment balance for subsequent accounting periods.
Cash and Cash Equivalents
For purposes of the consolidated balance sheets and statements of cash flow, ProAssurance considers all demand deposits and overnight investments to be cash equivalents.
Restricted Cash
Restricted cash represents cash balances which are not available for immediate or general use. At December 31, 2013 ProAssurance's Restricted cash was comprised entirely of a deposit collateralizing a standby letter of credit entered into as a part of our funding at Lloyd's.
Deferred Policy Acquisition Costs
Costs that vary with and are directly related to the successful production of new and renewal premiums (primarily premium taxes, commissions and underwriting salaries) are deferred to the extent they are recoverable against unearned premiums and are amortized as related premiums are earned.
Income Taxes/Deferred Taxes
ProAssurance files a consolidated federal income tax return. Tax-related interest and penalties are recognized as components of tax expense.
ProAssurance evaluates tax positions taken on tax returns and recognizes positions in the financial statements when it is more likely than not that the position will be sustained upon resolution with a taxing authority. If recognized, the benefit is measured as the largest amount of benefit that has a greater than fifty percent probability of being realized. Uncertain tax positions are reviewed each period by considering changes in facts and circumstances, such as changes in tax law, interactions with taxing authorities and developments in case law, and adjustments are made as considered necessary. Adjustments to unrecognized tax benefits may affect income tax expense and the settlement of uncertain tax positions may require the use of cash.
Deferred federal income taxes arise from the recognition of temporary differences between the basis of assets and liabilities determined for financial reporting purposes and the basis determined for income tax purposes. ProAssurance’s temporary differences principally relate to loss reserves, unearned premium, deferred policy acquisition costs, unrealized investment gains (losses), basis differentials for investments, compensation accruals, and intangibles. Deferred tax assets and liabilities are measured using the enacted tax rates expected to be in effect when such benefits are realized. ProAssurance reviews its deferred tax assets quarterly for impairment. If management determines that it is more likely than not that some or all of a deferred tax asset will not be realized, a valuation allowance is recorded to reduce the carrying value of the asset. In assessing the need for a valuation allowance, management is required to make certain judgments and assumptions about the future operations of ProAssurance based on historical experience and information as of the measurement period regarding reversal of existing temporary differences, carryback capacity, future taxable income, including its capital and operating characteristics, and tax planning strategies.
Changes in tax laws and rates could also affect recorded deferred tax assets and liabilities in the future. Management is not aware of any such changes that would have a material effect on the Company’s results of operations, cash flows or financial position.
Real Estate
Real Estate balances are reported at cost or, for properties acquired in business combinations, estimated fair value on the date of acquisition, less accumulated depreciation. Real estate principally consists of properties in use as corporate offices. Depreciation is computed over the estimated useful lives of the related property using the straight-line method. Excess office capacity is leased or made available for lease; rental income is included in other income and real estate expenses are included in underwriting, policy acquisition and operating expenses.
Real estate accumulated depreciation was approximately $21.6 million and $20.2 million at December 31, 2013 and 2012, respectively. Real estate depreciation expense for the years ended December 31, 2013, 2012 and 2011 was $1.5 million, $1.4 million and $1.7 million, respectively.
Intangible Assets
Intangible assets with definite lives are amortized over the estimated useful life of the asset. Amortizable intangible assets primarily consist of renewal rights and agency relationships and had a carrying value of $51.7 million and $50.2 million at December 31, 2013 and 2012, respectively. Intangible assets with an indefinite life, primarily state licenses, are not amortized and had carrying values of $16.8 million and $14.3 million at December 31, 2013 and 2012, respectively. Increases in both amortizable and non-amortizable intangible assets during 2013 were attributable to intangible assets recognized related to 2013 business combinations. Intangible assets are evaluated for impairment on an annual basis.
Accumulated amortization of intangible assets was $16.5 million and $11.2 million at December 31, 2013 and 2012, respectively. Amortization expense for intangible assets for the three years ended December 31, 2013, 2012 and 2011 was $5.3 million, $4.5 million and $4.7 million, respectively. Aggregate amortization expense for intangible assets, excluding amortizable intangible assets recorded through our acquisition of Eastern, is estimated to be $5.1 million for 2014, $3.1 million for 2015, $2.8 million for 2016, $2.8 million for 2017 and $2.4 million for 2018.
Goodwill
ProAssurance makes at least an annual assessment as to whether the value of its goodwill assets are impaired. Management evaluates the carrying value of goodwill annually on October 1 and before the annual evaluation if events occur or circumstances change that would more likely than not reduce the fair value below the carrying value. Because ProAssurance operates in a single operating segment and all components within the segment are economically similar, ProAssurance is considered a single reporting unit for the purposes of the impairment evaluation. In assessing goodwill, Management estimates the fair value of the reporting unit on the evaluation date based on the Company’s market capitalization and an expected premium that would be paid to acquire control of the Company (a control premium) and performs a sensitivity analysis using a range of historical stock prices and control premiums. Management concluded in 2013, 2012 and 2011 that the fair value of the Company’s reporting unit exceeded the carrying value and no adjustment to impair goodwill was necessary.
Goodwill is recognized in conjunction with acquisitions as the excess of the purchase consideration for the acquisition over the fair value of identifiable assets acquired and liabilities assumed. The fair value of identifiable assets and liabilities, and thus goodwill, is subject to redetermination within a measurement period of up to one year following completion of an acquisition. During 2013 goodwill was reduced by $1.9 million primarily related to the after-tax effect of the re-determination of the fair value of the reserve for losses associated with a business combination completed in late 2012.
Other Assets
At December 31, 2013 and 2012, Other assets was principally comprised of deposits with third-party agents of $205 million and $153.7 million, respectively, related to the completion of pending business combination transactions. See Note 2.
Treasury Stock
Treasury shares are reported at cost, and are reflected on the balance sheets as an unallocated reduction of total equity.
Share-Based Payments
ProAssurance recognizes compensation cost for share-based payments (including stock options, performance share units, restricted share units, and purchase match units) using the modified prospective method whereby the methodology for recognizing compensation expense differs depending upon the grant date of each share-based payment award. Compensation cost for awards is recognized based on the grant-date fair value of the award over the relevant service period of the award; for awards that vest in increments (graded vesting), compensation cost is recognized over the relevant service period for each separately vested portion of the award. Excess tax benefits (tax deductions realized in excess of the compensation costs recognized for the exercise of the awards, multiplied by the incremental tax rate) are reported as financing cash inflows.
Subsequent Events
In connection with its preparation of the Consolidated Financial Statements, ProAssurance has evaluated events that occurred subsequent to December 31, 2013, for recognition or disclosure in its financial statements and notes to the financial statements.
Accounting Changes Adopted
Intangibles-Goodwill and Other
Effective for fiscal years beginning after September 15, 2012, the Financial Accounting Standards Board (FASB) revised guidance related to impairment testing of indefinite-lived intangible assets. The new guidance permits an entity to assess qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that an indefinite-lived intangible asset is impaired. Quantitative impairment testing is required only if the assessment of qualitative factors indicates it is more likely than not that impairment exists. ProAssurance adopted the guidance on January 1, 2013. Adoption of this guidance had no material effect on ProAssurance's results of operations or financial position.
Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
Effective for interim and annual reporting periods beginning after December 15, 2012, the FASB revised guidance related to the disclosure of amounts reclassified out of accumulated other comprehensive income. The most significant provisions of the new guidance require entities to present additional disclosure, either on the face of the income statement or in the notes, regarding significant amounts reclassified, in their entirety, from accumulated other comprehensive income to net income. ProAssurance adopted the guidance on January 1, 2013. Adoption of this guidance had no material effect on ProAssurance’s results of operations or financial position as it impacts disclosures only.
Disclosures About Offsetting Assets and Liabilities
Effective for fiscal years beginning on or after January 1, 2013, the FASB revised guidance related to disclosures about certain assets and liabilities in an entity’s financial statements. The guidance requires disclosures related to the net and gross positions of certain financial instruments and transactions that are either eligible for offset in accordance with existing GAAP guidance or subject to an agreement that requires such offset. The guidance must be applied retrospectively for all prior periods presented. ProAssurance adopted the guidance on January 1, 2013. Adoption of this guidance had no material effect on ProAssurance’s results of operations or financial position as it impacts disclosures only.
Accounting for Costs Associated with Acquiring or Renewing Insurance Contracts
Effective for fiscal years beginning after December 15, 2011, the FASB revised guidance regarding the interpretation of which costs relating to the acquisition of new or renewal insurance contracts qualify for deferral. The guidance permits deferral of qualifying costs only when associated with successful contract acquisitions. Internal selling agent and underwriter salary and benefit costs allocated to unsuccessful contracts, as well as advertising costs, are excluded. The guidance permitted but did not require retrospective application. ProAssurance prospectively adopted the guidance on January 1, 2012. Adoption of this guidance had no material effect on ProAssurance’s results of operations or financial position.
Accounting Changes Not Yet Adopted
Investments-Equity Method and Joint Ventures-Accounting for Investments in Qualified Affordable Housing Projects
Effective for fiscal years beginning after December 15, 2014, the FASB issued guidance which permits qualified reporting entities to use a new accounting method, the proportional amortization method, for investments in qualified affordable housing projects. Under the new method the initial cost of an investment is amortized in proportion to the tax benefits received, and investment performance is recognized as a component of income tax expense (benefit) rather than as a component of investment income. ProAssurance is in the process of evaluating the effect that the use of the new method would have on its results of operations and financial position and whether it meets the qualification requirements for using the new method. ProAssurance plans to adopt the guidance beginning January 1, 2015.
Liabilities-Obligations Resulting from Joint and Several Liability Arrangements
Effective for fiscal years beginning after December 15, 2013, the FASB revised guidance related to obligations resulting from joint and several liability arrangements. The new guidance requires an entity to recognize, measure and disclose obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date, except for obligations already addressed within existing GAAP guidance, with retrospective application required for such arrangements existing at the beginning of the fiscal year of adoption. ProAssurance plans to adopt the guidance beginning January 1, 2014. Adoption of this guidance is expected to have no effect on ProAssurance's results of operations or financial position.
Income Taxes-Presentation of Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
Effective for fiscal years beginning after December 15, 2013, the FASB issued guidance related to the financial statement presentation of unrecognized tax benefits. The new guidance requires an entity to present unrecognized tax benefits as a reduction to a deferred tax asset resulting from a net operating loss carryforward, a similar tax loss, or tax credit carryforward except in circumstances where the relevant taxing authority does not permit offset or does not require offset and the entity does not intend to use the deferred tax asset for offset. The guidance requires prospective application for all unrecognized tax benefits that exist as of the effective date, but may be applied retrospectively. ProAssurance plans to adopt the guidance prospectively beginning January 1, 2014. Adoption of this guidance is expected to have no effect on ProAssurance's results of operations or financial position.

Business_Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Business Combinations	'
	Business Combinations
	All entities acquired in 2013 and 2012 were accounted for in accordance with GAAP relating to business combinations. No entities were acquired in 2011.
	On January 1, 2013, ProAssurance completed the acquisition of Medmarc Mutual Insurance Company, now Medmarc Casualty Insurance Company (Medmarc), through a sponsored demutualization. Medmarc is based in Chantilly, Virginia and provides products liability insurance for medical technology and life sciences companies and also provides legal professional liability insurance. ProAssurance acquired Medmarc for cash of $153.7 million, including the funding of future policy credits for eligible members of $7.5 million. ProAssurance transferred all of the cash required to complete the transaction to a third-party agent for the benefit of Medmarc eligible members on December 27, 2012; the deposit was classified as a part of Other Assets at December 31, 2012. ProAssurance incurred expenses related to the purchase of approximately $2.6 million during the year ended December 31, 2013 and approximately $1.0 million during the year ended December 31, 2012. These expenses were included as a part of operating expenses in the periods incurred.
	The purchase consideration for Medmarc was allocated to the assets acquired and liabilities assumed based on their estimated fair values on the acquisition date, as shown in the table below. The purchase consideration was less than the estimated fair value of the net assets acquired resulting in a gain on the acquisition of $32.3 million, which reflects a reduction of $3.7 million recorded in the fourth quarter of 2013, as discussed in Note 1. ProAssurance believes it was able to acquire Medmarc for less than the fair value of its net assets due to Medmarc's declining premium base and its small capital position relative to other insurers in the medical technology and life sciences products liability insurance market.
	(In thousands)
	Fixed maturities, available for sale		$	269,529
	Equity securities, trading		30,976
	Cash and short-term investments		24,008
	Other investments		5,340
	Premiums receivable		2,986
	Receivable from reinsurers on paid and unpaid losses and LAE		73,107
	Intangible assets		3,630
	Other assets		14,614
	Reserve for losses and loss adjustment expenses		(201,072		)
	Unearned premiums		(16,937		)
	Deferred tax liabilities		(4,934		)
	Other liabilities		(15,233		)
	Fair value of net assets acquired		$	186,014
	Gain on Acquisition		(32,314		)
	Total purchase consideration		$	153,700
	Intangible assets acquired principally consist of non-compete agreements, which are amortizable over their useful life of two years, and insurance licenses, which have an indefinite useful life and are not amortized.
	ProAssurance believes that all contractual cash flows related to acquired receivables will be collected. The fair value of reserves for losses and loss adjustment expenses and related reinsurance recoverables were estimated based on the present value of the expected underlying net cash flows, including a 5% profit margin and a 5% risk premium, and were determined to be materially the same as the recorded cost basis acquired.
	The following table provides Pro Forma Consolidated Results for the years ended December 31, 2013 and 2012 as if the Medmarc transaction had occurred on January 1, 2012. Pro Forma Consolidated Results reflect ProAssurance Actual Consolidated Results adjusted by the following, net of related tax effects:
	•	For the year ended December 31, 2012, the ProAssurance 2012 Actual Consolidated Results did not include Medmarc, and have been adjusted to include Medmarc's 2012 operating results. ProAssurance Actual Consolidated Results for the year ended December 31, 2013 included Medmarc operating results (Revenue of $46.5 million and Net Income of $15.7 million).
	•	Certain costs included in ProAssurance Actual Consolidated Results for the year ended December 31, 2013 have been reported in the Pro Forma Consolidated Results as if the costs had been incurred for the year ended December 31, 2012. Such costs include direct transaction costs and certain compensation costs directly related to the integration of Medmarc operations.
	•	Prior to the acquisition date, Medmarc reported on a statutory basis and expensed policy acquisition costs associated with successful contracts as incurred. After the acquisition date, in accordance with GAAP, Medmarc policy acquisition costs associated with successful contracts were capitalized and amortized to expense as the related premium revenues were earned, but no amortization was recognized for Medmarc policies written prior to the acquisition date. The Pro Forma Consolidated Results for both 2013 and 2012 have been adjusted to reflect policy acquisition costs as if Medmarc had followed GAAP guidance for these costs in pre-acquisition periods.
	•	Earnings for the year ended December 31, 2012 were reduced to reflect amortization of intangible assets and debt security premiums and discounts recorded as a part of the Medmarc purchase price allocation.
	•	The non-taxable gain on the acquisition of $32.3 million that was included in ProAssurance Actual Consolidated Results for the year ended December 31, 2013 has been reported in the Pro Forma Consolidated Results as being recognized during the year ended December 31, 2012.
		Year Ended December 31, 2013				Year Ended December 31, 2012
	(In thousands)	ProAssurance		ProAssurance		ProAssurance	ProAssurance
		Pro Forma		Actual		Pro Forma	Actual
		Consolidated		Consolidated Results		Consolidated	Consolidated Results
		Results				Results
	Revenue	$740,178		$740,178		$757,240	$715,854
	Net Income	$263,820		$297,523		$317,097	$275,470
	During 2012, ProAssurance also completed an acquisition of a reciprocal exchange that converted to a stock insurance company upon acquisition. The acquisition was not material to ProAssurance.
	On January 1, 2014, ProAssurance completed the acquisition of Eastern Insurance Holdings, Inc. (Eastern) (NASDAQ: EIHI) by purchasing 100% of its outstanding common shares for cash of $205 million. Eastern is based in Lancaster, Pennsylvania and specializes in workers' compensation insurance and reinsurance products and services, including a segregated portfolio cell reinsurance business. Allocation of the Eastern purchase consideration to the assets acquired and liabilities assumed was not complete as of the date of this report. ProAssurance transferred all of the cash required to complete the transaction to a third-party agent for the benefit of Eastern eligible shareholders on December 27, 2013; the deposit was classified as a part of Other Assets at December 31, 2013.

Fair_Value_Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurement	'
	Fair Value Measurement
	Fair value is defined 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. A three level hierarchy has been established for valuing assets and liabilities based on how transparent (observable) the inputs are that are used to determine fair value, with the inputs considered most observable categorized as Level 1 and those that are the least observable categorized as Level 3. Hierarchy levels are defined as follows:
		Level 1:	quoted (unadjusted) market prices in active markets for identical assets and liabilities. For ProAssurance, Level 1 inputs are generally quotes for debt or equity securities actively traded in exchange or over-the-counter markets.
		Level 2:	market data obtained from sources independent of the reporting entity (observable inputs). For ProAssurance, Level 2 inputs generally include quoted prices in markets that are not active, quoted prices for similar assets or liabilities, and results from pricing models that use observable inputs such as interest rates and yield curves that are generally available at commonly quoted intervals.
		Level 3:	the reporting entity’s own assumptions about market participant assumptions based on the best information available in the circumstances (non-observable inputs). For ProAssurance, Level 3 inputs are used in situations where little or no Level 1 or 2 inputs are available or are inappropriate given the particular circumstances. Level 3 inputs include results from pricing models for which some or all of the inputs are not observable, discounted cash flow methodologies, single non-binding broker quotes and adjustments to externally quoted prices that are based on management judgment or estimation.
	Fair values of assets measured at fair value on a recurring basis as of December 31, 2013 and December 31, 2012, including financial instruments for which ProAssurance has elected fair value, are shown in the following tables. The tables also indicate the fair value hierarchy of the valuation techniques utilized to determine those fair values. For some assets, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. When this is the case, the asset is categorized based on the level of the most significant input to the fair value measurement. Assessments of the significance of a particular input to the fair value measurement requires judgment and consideration of factors specific to the assets being valued.
		31-Dec-13
		Fair Value Measurements Using											Total
	(In thousands)	Level 1				Level 2				Level 3			Fair Value
	Assets:
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	—			$	170,714			$	—		$	170,714
	U.S. Government-sponsored enterprise obligations	—				32,768				—			32,768
	State and municipal bonds	—				1,147,328				7,338			1,154,666
	Corporate debt, multiple observable inputs	—				1,346,977				—			1,346,977
	Corporate debt, limited observable inputs:
	Other corporate debt, NRSRO ratings available	—				—				11,449			11,449
	Other corporate debt, NRSRO ratings not available	—				—				2,727			2,727
	Residential mortgage-backed securities	—				235,614				—			235,614
	Agency commercial mortgage-backed securities	—				27,475				—			27,475
	Other commercial mortgage-backed securities	—				61,390				—			61,390
	Other asset-backed securities	—				67,455				6,814			74,269
	Equity securities
	Financial	81,536				—				—			81,536
	Utilities/Energy	32,350				—				—			32,350
	Consumer oriented	66,461				—				—			66,461
	Industrial	57,262				—				—			57,262
	All other	15,932				—				—			15,932
	Short-term investments	248,605				—				—			248,605
	Financial instruments carried at fair value, classified as a part of:
	Investment in unconsolidated subsidiaries	—				—				72,062			72,062
	Total assets	$	502,146			$	3,089,721			$	100,390		$	3,692,257
		31-Dec-12
		Fair Value Measurements Using											Total
	(In thousands)	Level 1				Level 2				Level 3			Fair Value
	Assets:
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	—			$	205,857			$	—		$	205,857
	U.S. Government-sponsored enterprise obligations	—				56,947				—			56,947
	State and municipal bonds	—				1,212,804				7,175			1,219,979
	Corporate debt, multiple observable inputs	—				1,455,333				—			1,455,333
	Corporate debt, limited observable inputs:
	Private placement senior notes	—				—				346			346
	Other corporate debt, NRSRO ratings available	—				—				13,835			13,835
	Other corporate debt, NRSRO ratings not available	—				—				1,010			1,010
	Residential mortgage-backed securities	—				289,850				—			289,850
	Agency commercial mortgage-backed securities	—				59,464				—			59,464
	Other commercial mortgage-backed securities	—				74,106				—			74,106
	Other asset-backed securities	—				67,237				4,035			71,272
	Equity securities
	Financial	70,900				—				—			70,900
	Utilities/Energy	31,383				—				—			31,383
	Consumer oriented	51,100				—				—			51,100
	Industrial	29,695				—				—			29,695
	All other	19,540				—				—			19,540
	Short-term investments	59,761				11,976				—			71,737
	Financial instruments carried at fair value, classified as a part of:
	Investment in unconsolidated subsidiaries	—				—				33,739			33,739
	Total assets	$	262,379			$	3,433,574			$	60,140		$	3,756,093
	The fair values for securities included in the Level 2 category, with the few exceptions described below, have been developed by one of several third party, nationally recognized pricing services, including services that price only certain types of securities. Each service uses complex methodologies to determine values for securities and subject the values they develop to quality control reviews. Management has selected a primary source for each type of security in the portfolio, and reviews the values provided for reasonableness by comparing data to alternate pricing services and to available market and trade data. Values that appear inconsistent are further reviewed for appropriateness. If a value does not appear reasonable, the valuation is discussed with the service that provided the value and would be adjusted, if necessary. No such adjustments were necessary in 2013 or 2012.
	Level 2 Valuations
	Below is a summary description of the valuation methodologies primarily used by the pricing services for securities in the Level 2 category, by security type:
	U.S. Treasury obligations are valued based on quoted prices for identical assets, or, in markets that are not active, quotes for similar assets, taking into consideration adjustments for variations in contractual cash flows and yields to maturity.
U.S. Government-sponsored enterprise obligations are valued using pricing models that consider current and historical market data, normal trading conventions, credit ratings, and the particular structure and characteristics of the security being valued, such as yield to maturity, redemption options, and contractual cash flows. Adjustments to model inputs or model results are included in the valuation process when necessary to reflect recent regulatory, government or corporate actions or significant economic, industry or geographic events that would affect the security’s fair value.
State and municipal bonds are valued using a series of matrices that consider credit ratings, the structure of the security, the sector in which the security falls, yields, and contractual cash flows. Valuations are further adjusted, when necessary, to reflect recent significant economic or geographic events or ratings changes that would affect the security’s fair value.
Corporate debt with multiple observable inputs consists primarily of corporate bonds, but also includes a small number of bank loans. The methodology used to value Level 2 corporate bonds is the same as the methodology previously described for U.S. Government-sponsored enterprise obligations. Bank loans are valued by an outside vendor based upon a widely distributed, loan-specific listing of average bid and ask prices published daily by an investment industry group. The publisher of the listing derives the averages from data received from multiple market-makers for bank loans.
Residential and commercial mortgage backed securities. Agency pass-through securities are valued using a matrix, considering the issuer type, coupon rate and longest cash flows outstanding. The matrix is developed daily based on available market information. Agency and non-agency collateralized mortgage obligations are both valued using models that consider the structure of the security, current and historical information regarding prepayment speeds, ratings and ratings updates, and current and historical interest rate and interest rate spread data. Valuations of Alt-A mortgages include a review of collateral performance data, which is generally updated monthly.
Other asset-backed securities are valued using models that consider the structure of the security, monthly payment information, current and historical information regarding prepayment speeds, ratings and ratings updates, and current and historical interest rate and interest rate spread data. Spreads and prepayment speeds consider collateral type. Valuations of subprime home equity loans use the same valuation methodology as previously described for Alt-A mortgages.
Short-term investments are securities maturing within one year, carried at cost which approximates the fair value of the security due to the short term to maturity.
Level 3 Valuations
Below is a summary description of the valuation processes and methodologies used as well as quantitative information regarding securities in the Level 3 category.
Level 3 Valuation Processes
•	Level 3 securities are priced by the Vice President of Investments for our subsidiaries, who reports to the Chief Financial Officer.
•	Level 3 valuations are computed quarterly. Prices are evaluated quarterly against prior period prices and the expected change in price.
•	Exclusive of Investments in unconsolidated subsidiaries, which are valued at net asset value (NAV), the securities noted in the disclosure are primarily NRSRO rated corporate debt instruments for which comparable market inputs are commonly available for evaluating the securities in question. Valuation of these corporate debt instruments is not overly sensitive to changes in the unobservable inputs used.
Level 3 Valuation Methodologies
State and municipal bonds consists of auction rate municipal bonds valued internally using either published quotes for similar securities or values produced by discounted cash flow models using yields currently available on fixed rate securities with a similar term and collateral, adjusted to consider the effect of a floating rate and a premium for illiquidity. At December 31, 2013, 99% of the securities were rated; the average rating was A.
Corporate debt with limited observable inputs consists of corporate bonds and, at December 31, 2012, private placement senior notes guaranteed by large regional banks. Valuations are determined using dealer quotes for similar securities or discounted cash flow models using yields currently available for similar securities. Similar securities are defined as securities having like terms and payment features that are of comparable credit quality. Assessments of credit quality are based on NRSRO ratings, if available, or are subjectively determined by management if not available. At December 31, 2013, the average rating of rated securities was A-.
Other asset-backed securities consists of securitizations of receivables valued using dealer quotes for similar securities or discounted cash flow models using yields currently available for similar securities.
Investment in unconsolidated subsidiaries consist of limited partnership (LP) and limited liability company (LLC) interests valued using the NAV provided by the LP/LLC, which approximates the fair value of the interest.
Such interests include the following:
	Unfunded	Fair Value
	Commitments
(In thousands)	December 31,	December 31,				December 31,
	2013	2013				2012
Investments in LPs/LLCs:
Secured debt fund (1)	$27,000	$	13,233			$	—
Long equity fund (2)	None	6,574				—
Long/Short equity funds (3)	None	28,385				17,115
Non-public equity funds (4)	87,603	23,870				16,624
		$	72,062			$	33,739
-1	The LP is structured to provide income and capital appreciation primarily through investments in senior secured debt. Redemptions are not allowed. Income and capital are to be periodically distributed at the discretion of the LP over an anticipated time frame that spans from 7 to 9 years.
-2	The LP holds long equities of public international companies. Redemptions are allowed at the end of any calendar month with a prior notice requirement of 15 days and are paid within 10 days of the end of the calendar month of the redemption request.
-3	Comprised of interests in two unrelated LP funds, each holds primarily long and short U.S. and North American equities, and targets absolute returns using a strategy designed to take advantage of event-driven market opportunities. One LP allows redemption with a notice requirement of up to 45 days with the redemption payable within 30 days of the redemption date, unless the redemption request is for 90% or more of the requestor’s capital balance. Redemptions at the 90% and above level will be paid at 90%, with the remainder paid after the LP’s annual audit. The other LP generally allows redemption of substantially all the capital semi-annually with 30 days notice.
-4	Comprised of interests in three unrelated LP funds, each structured to provide capital appreciation through diversified investments in private equity, which can include investments in buyout, venture capital, mezzanine debt, distressed debt and other private equity-oriented LPs. One LP allows redemption by special consent; the others do not permit redemption. Income and capital are to be periodically distributed at the discretion of the LP over time frames that are anticipated to span from 4 to 12 years.
Quantitative Information Regarding Level 3 Valuations
Quantitative Information about Level 3 Fair Value Measurements
		Fair Value at
(In millions)		31-Dec-13		31-Dec-12		Valuation Technique		Unobservable Input		Range
										(Weighted Average)
Assets:
State and municipal bonds		$7.30		$7.20		Market Comparable		Comparability Adjustment		0% - 10% (5%)
						Securities
						Discounted Cash Flows		Comparability Adjustment		0% - 10% (5%)
Corporate debt with limited observable inputs		$14.20		$15.20		Market Comparable		Comparability Adjustment		0% - 5% (2.5%)
						Securities
						Discounted Cash Flows		Comparability Adjustment		0% - 5% (2.5%)
Other asset-backed securities		$6.80		$4.00		Market Comparable		Comparability Adjustment		0% - 5% (2.5%)
						Securities
						Discounted Cash Flows		Comparability Adjustment		0% - 5% (2.5%)
The significant unobservable inputs used in the fair value measurement of the entity’s corporate bonds are the valuations of comparable securities with similar issuer, credit quality and maturity. Changes in the availability of comparable securities could result in changes in the fair value measurements.
Fair Value Measurements - Level 3 Assets
The following tables (the Level 3 Tables) present summary information regarding changes in the fair value of assets measured at fair value using Level 3 inputs.
	31-Dec-13
	Level 3 Fair Value Measurements – Assets
(In thousands)	State and Municipal Bonds				Corporate Debt				Asset-backed Securities			Investment in Unconsolidated Subsidiaries			Other Investments			Total
Balance December 31, 2012	$	7,175			$	15,191			$	4,035		$	33,739		$	—		$	60,140
Total gains (losses) realized and unrealized:
Included in earnings, as a part of:
Net investment income	—				(103		)		(17		)	—			—			(120		)
Equity in earnings of unconsolidated subsidiaries	—				—				—			6,877			—			6,877
Net realized investment gains (losses)	(44		)		(69		)		—			—			—			(113		)
Included in other comprehensive income	1				(725		)		(61		)	—			—			(785		)
Purchases	—				9,470				1,356			24,567			—			35,393
Sales	(2,106		)		(1,629		)		(18		)	(14,632		)	—			(18,385		)
Transfers in	2,312				2,114				3,800			21,511			—			29,737
Transfers out	—				(10,073		)		(2,281		)	—			—			(12,354		)
Balance December 31, 2013	$	7,338			$	14,176			$	6,814		$	72,062		$	—		$	100,390
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	$	—			$	—			$	—		$	6,877		$	—		$	6,877
	31-Dec-12
	Level 3 Fair Value Measurements – Assets
(In thousands)	State and Municipal Bonds				Corporate Debt				Asset-backed Securities			Investment in Unconsolidated Subsidiaries			Other Investments			Total
Balance December 31, 2011	$	7,200			$	8,082			$	—		$	23,841		$	15,873		$	54,996
Total gains (losses) realized and unrealized:
Included in earnings, as a part of:
Net investment income	—				14				—			—			—			14
Equity in earnings of unconsolidated subsidiaries	—				—				—			278			—			278
Net realized investment gains (losses)	—				10				—			—			(131		)	(121		)
Included in other comprehensive income	—				611				35			—			—			646
Purchases	—				3,136				6,734			11,008			—			20,878
Sales	(25		)		(1,951		)		(1,118		)	(1,388		)	—			(4,482		)
Transfers in	—				9,220				—			—			—			9,220
Transfers out	—				(3,931		)		(1,616		)	—			(15,742		)	(21,289		)
Balance December 31, 2012	$	7,175			$	15,191			$	4,035		$	33,739		$	—		$	60,140
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	$	—			$	—			$	—		$	278		$	(131	)	$	147
Transfers
There were no transfers between the Level 1 and Level 2 categories during 2012. Short-term investments of $7.2 million were transferred from Level 2 to Level 1 as of the end of 2013.
Transfers shown in the preceding Level 3 Tables were as of the end of the period and were to or from Level 2, unless otherwise noted.
The transfer in for Investment in unconsolidated subsidiaries reported in the Level 3 Tables for 2013 reflected an interest in an LP previously accounted for using the cost method and thus not carried at fair value. During 2013, the interest began to be accounted for using the equity method which approximates fair value.
Transfers of Other investments reported in the Level 3 Tables for 2012 related to an interest in an LLC. The LLC converted into a publicly traded investment fund during 2012 and the interest was valued using Level 1 inputs at December 31, 2012.
All remaining transfers during 2013 and 2012 related to securities held for which the level of market activity for identical or nearly identical securities varies from period to period. The securities were valued using multiple observable inputs when those inputs were available; otherwise the securities were valued using limited observable inputs.
Fair Value Measurements - Level 3 Liabilities
The following table presents information for the year ended December 31, 2012 regarding liabilities for which ProAssurance had elected fair value treatment at December 31, 2011 and during 2012.
	31-Dec-12
	Level 3 Fair Value Measurements - Liabilities
(In thousands)	2019 Note Payable				Interest rate swap agreement				Total
Balance December 31, 2011	$	14,180			$	4,659			$	18,839
Total (gains) losses realized and unrealized:
Included in earnings as a part of:
Net realized investment (gains) losses	769				476				1,245
Loss on extinguishment of debt	2,163				—				2,163
Settlements	(17,112		)		(5,135		)		(22,247		)
Balance December 31, 2012	$	—			$	—			$	—
Change in unrealized (gains) losses included in earnings for the above period for Level 3 liabilities outstanding at period-end	$	—			$	—			$	—
At December 31, 2011 ProAssurance held a note payable, the 2019 Note Payable, and a related interest rate swap agreement (the Swap), both of which were measured at fair value on a recurring basis, with changes in fair value recorded in net realized investment gains (losses). ProAssurance assumed both liabilities as part of a previous acquisition. The fair value option was elected for each because valuation at fair value better reflected the economics of the related liabilities and eliminated the inconsistency that would have otherwise resulted from carrying the 2019 Note Payable on an amortized cost basis and the Swap at fair value. Both liabilities were repaid in July 2012. The fair values of these liabilities were determined using the present value of the expected underlying cash flows of each instrument, discounted at rates available on the valuation date for similar instruments issued by entities with a similar credit standing to ProAssurance.
Financial Instruments - Methodologies Other Than Fair Value
The following table provides the estimated fair value of our financial instruments that, in accordance with GAAP for the type of investment, are measured using a methodology other than fair value. All fair values provided fall within the Level 3 fair value category.
	31-Dec-13								31-Dec-12
(In thousands)	Carrying				Fair				Carrying			Fair
	Value				Value				Value			Value
Financial assets:
BOLI	$	54,374			$	54,374			$	31,085		$	38,656
Investment in unconsolidated subsidiaries	142,174				139,548				87,310			91,528
Other investments	52,240				51,833				52,414			52,414
Other assets	17,940				17,940				11,400			11,385
Financial liabilities:
Senior notes due 2023	$	250,000			$	262,500			$	—		$	—
Revolving credit agreement	—				—				125,000			125,000
Other liabilities	13,303				13,303				12,130			12,085
The fair value of the BOLI was equal to the cash surrender value associated with the policies on the valuation date.
Investment in unconsolidated subsidiaries consisted of investments in tax credit partnerships, accounted for using the equity method with the carrying value approximating ProAssurance’s initial investment commitment to the partnership less a pro rata portion of partnership operating losses over the period the investment has been held. The estimated fair value of the partnership is based on the net present value of the expected cash flows from the partnership and considers the timing of tax benefits expected to be received, the funding schedule for the partnership, and current rates for investments with similar risk structures and repayment periods.
Other investments listed in the table above include interests in certain investment fund LPs/LLCs accounted for using the cost method, investments in Federal Home Loan Bank (FHLB) common stock carried at cost, and an annuity investment carried at amortized cost. The estimated fair value of the LP/LLC interests was based on the NAVs provided by the LP/LLC managers. The estimated fair value of the FHLB common stock was based on the amount ProAssurance would receive if its membership were canceled, as the membership cannot be sold. The fair value of the annuity was the present value of the expected future cash flows discounted using a rate available in active markets for similarly structured instruments. Other assets and Other liabilities primarily consisted of related investment assets and liabilities associated with funded deferred compensation agreements. Fair values of the funded deferred compensation assets and liabilities were based on the NAVs of the underlying securities. Other assets also included a secured note receivable and an unsecured receivable under a revolving credit agreement. Fair value of these receivables was based on the present value of expected cash flows from the receivables, discounted at market rates on the valuation date for receivables with similar credit standings and similar payment structures. At December 31, 2012, Other liabilities also included certain contractual liabilities related to prior business combinations. The fair values of the business combination liabilities were based on the present value of the expected future cash outflows, discounted at ProAssurance’s assumed incremental borrowing rate on the valuation date for unsecured liabilities with similar repayment structures.
The fair values of the long-term debt and revolving credit agreement were estimated based on the present value of expected future cash outflows, discounted at rates available on the valuation date for similar debt issued by entities with a similar credit standing to ProAssurance.

Investments

Investments	12 Months Ended
	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'
Investments	'
	Investments
	Available-for-sale securities at December 31, 2013 and December 31, 2012 included the following:
		31-Dec-13
	(In thousands)	Amortized			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
		Cost
	Fixed maturities
	U.S. Treasury obligations	$	166,115		$	6,118			$	(1,519	)		$	170,714
	U.S. Government-sponsored enterprise obligations	30,942			2,251				(425		)		32,768
	State and municipal bonds	1,116,060			46,533				(7,927		)		1,154,666
	Corporate debt	1,321,838			53,059				(13,744		)		1,361,153
	Residential mortgage-backed securities	230,861			7,608				(2,855		)		235,614
	Agency commercial mortgage-backed securities	27,268			343				(136		)		27,475
	Other commercial mortgage-backed securities	59,066			2,491				(167		)		61,390
	Other asset-backed securities	74,106			487				(324		)		74,269
		$	3,026,256		$	118,890			$	(27,097	)		$	3,118,049
		31-Dec-12
	(In thousands)	Amortized			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
		Cost
	Fixed maturities
	U.S. Treasury obligations	$	191,642		$	14,266			$	(51	)		$	205,857
	U.S. Government-sponsored enterprise obligations	52,110			4,837				—				56,947
	State and municipal bonds	1,134,744			85,329				(94		)		1,219,979
	Corporate debt	1,375,880			96,187				(1,543		)		1,470,524
	Residential mortgage-backed securities	272,990			17,070				(210		)		289,850
	Agency commercial mortgage-backed securities	57,234			2,255				(25		)		59,464
	Other commercial mortgage-backed securities	69,062			5,049				(5		)		74,106
	Other asset-backed securities	70,670			1,203				(601		)		71,272
		3,224,332			226,196				(2,529		)		3,447,999
	The recorded amortized cost basis and estimated fair value of available-for-sale fixed maturities at December 31, 2013, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
	(In thousands)	Amortized			Due in one				Due after				Due after			Due after		Total Fair
		Cost			year or less				one year				five years			ten years		Value
									through				through
									five years				ten years
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	166,115		$	15,501			$	107,433			$	44,102		$	3,678	$	170,714
	U.S. Government-sponsored enterprise obligations	30,942			3,226				21,564				7,759			219		32,768
	State and municipal bonds	1,116,060			57,081				406,444				467,219			223,922		1,154,666
	Corporate debt	1,321,838			124,080				578,894				627,496			30,683		1,361,153
	Residential mortgage-backed securities	230,861																235,614
	Agency commercial mortgage-backed securities	27,268																27,475
	Other commercial mortgage-backed securities	59,066																61,390
	Other asset-backed securities	74,106																74,269
		$	3,026,256															$	3,118,049
	Excluding investments in bonds and notes of the U.S. Government and U.S. Government-sponsored enterprise obligations, no investment in any entity or its affiliates exceeded 10% of shareholders’ equity at December 31, 2013.
	Cash and securities with a carrying value of $36.3 million at December 31, 2013 were on deposit with various state insurance departments to meet regulatory requirements.
	BOLI
	ProAssurance holds BOLI policies on management employees that are carried at the current cash surrender value of the policies (original cost $33 million). The primary purpose of the program is to offset future employee benefit expenses through earnings on the cash value of the policies. ProAssurance is the owner and principal beneficiary of these policies.
	Other Investments
	Other Investments at December 31, 2013 and December 31, 2012 was comprised as follows:
	(In thousands)	December 31,			December 31,
		2013			2012
	Investments in LPs/LLCs, at cost	$	47,258		$	25,092
	FHLB capital stock, at cost	3,449			4,278
	Other, principally an annuity, at amortized cost	1,533			1,715
		$	52,240		$	31,085
	FHLB capital stock is not marketable, but may be liquidated by terminating membership in the FHLB. The liquidation process can take up to five years.
	Unconsolidated Subsidiaries
	ProAssurance holds investments in unconsolidated subsidiaries, accounted for under the equity method. The investments include the following:
		31-Dec-13						Carrying Value
	(In thousands)	Unfunded			Percentage			December 31,				December 31,
		Commitments*			Ownership			2013				2012
	Investment in LPs/LLCs:
	Tax credit partnerships	$	22,441		See below			$	142,174			$	87,310
Secured debt fund	27,000			<	20%		13,233				—
Long equity fund	None			<	20%		6,574				—
Long/Short equity funds	None			<	25%		28,385				17,115
Non-public equity funds	87,603			<	20%		23,870				16,624
							$	214,236			$	121,049
* Unfunded commitments are included in the carrying value of tax credit partnerships, only.
Tax credit partnership interests held by ProAssurance generate investment returns by providing tax benefits to fund investors in the form of project operating losses and tax credits. The related properties are principally low income housing projects. ProAssurance's ownership percentage relative to two of the tax credit partnership interests was almost 100%; these interests had a carrying value of $62.4 million at December 31, 2013. ProAssurance's ownership percentage relative to the remaining tax credit partnership interests was less than 20%; these interests had a carrying value of $79.8 million at December 31, 2013. All are accounted for under the equity method as ProAssurance does not have the ability to exert control over the partnerships.
The Secured debt fund is structured to provide interest distributions and capital appreciation primarily through investments in senior secured debt.
The Long equity fund targets long-term total returns through holdings in public international companies.
The Long/Short equity funds target absolute returns using strategies designed to take advantage of event-driven market opportunities. ProAssurance’s interest in one investment LP increased as other investors liquidated their holdings, and ProAssurance therefore determined it appropriate to begin applying the equity method of accounting instead of the previously applied cost method. When there is a change from the cost to the equity method, GAAP requires retroactive recording of accumulated earnings since the origination of the investment. As the amounts are not material in the current period or any of the prior periods affected, prior period financial statements have not been restated. Accordingly, Equity in earnings (loss) of unconsolidated subsidiaries for 2013 included our portion of the LP’s accumulated earnings from the date of initial investment, which totaled $10.5 million, $8.4 million of which was related to prior periods.
The Non-public equity funds hold diversified private equities and are structured to provide capital appreciation.
Investments Held in a Loss Position
The following tables provide summarized information with respect to investments held in an unrealized loss position at December 31, 2013 and December 31, 2012, including the length of time the investment had been held in a continuous unrealized loss position.
	31-Dec-13
	Total							Less than 12 months							12 months or longer
	Fair			Unrealized				Fair				Unrealized			Fair		Unrealized
(In thousands)	Value			Loss				Value				Loss			Value		Loss
Fixed maturities, available for sale
U.S. Treasury obligations	$	47,668		$	(1,519	)		$	44,304			$	(1,182	)	$	3,364	$	(337	)
U.S. Government-sponsored enterprise obligations	6,640			(425		)		5,752				(321		)	888		(104		)
State and municipal bonds	203,970			(7,927		)		184,401				(6,640		)	19,569		(1,287		)
Corporate debt	349,277			(13,744		)		324,510				(12,061		)	24,767		(1,683		)
Residential mortgage-backed securities	93,608			(2,855		)		84,045				(2,393		)	9,563		(462		)
Agency commercial mortgage-backed securities	11,658			(136		)		11,082				(116		)	576		(20		)
Other commercial mortgage-backed securities	11,153			(167		)		10,215				(159		)	938		(8		)
Other asset-backed securities	25,539			(324		)		21,804				(77		)	3,735		(247		)
	$	749,513		$	(27,097	)		$	686,113			$	(22,949	)	$	63,400	$	(4,148	)
Other investments
Investments in LPs/LLCs carried at cost	$	14,752		$	(1,059	)		$	13,166			$	(1,018	)	$	1,586	$	(41	)
	31-Dec-12
	Total							Less than 12 months							12 months or longer
	Fair			Unrealized				Fair				Unrealized			Fair		Unrealized
(In thousands)	Value			Loss				Value				Loss			Value		Loss
Fixed maturities, available for sale
U.S. Treasury obligations	$	4,073		$	(51	)		$	4,073			$	(51	)	$	—	$	—
State and municipal bonds	11,234			(94		)		9,232				(65		)	2,002		(29		)
Corporate debt	90,154			(1,543		)		81,878				(1,377		)	8,276		(166		)
Residential mortgage-backed securities	10,721			(210		)		10,029				(205		)	692		(5		)
Agency commercial mortgage-backed securities	1,643			(25		)		498				(2		)	1,145		(23		)
Other commercial mortgage-backed securities	2,100			(5		)		1,103				(1		)	997		(4		)
Other asset-backed securities	10,746			(601		)		7,707				(20		)	3,039		(581		)
	$	130,671		$	(2,529	)		$	114,520			$	(1,721	)	$	16,151	$	(808	)
Other investments
Investments in LPs/LLCs carried at cost	$	9,474		$	(851	)		$	8,697			$	(688	)	$	777	$	(163	)
As of December 31, 2013, excluding government backed securities, there were 714 debt securities (26.3% of all available-for-sale fixed maturity securities held) in an unrealized loss position representing 516 issuers. Both the single greatest and second greatest unrealized loss positions among those securities was approximately $0.4 million. The securities were evaluated for impairment as of December 31, 2013.
As of December 31, 2012, excluding government backed securities, there were 110 debt securities (4.4% of all available-for-sale fixed maturity securities held) in an unrealized loss position representing 93 issuers. The single greatest unrealized loss position among those securities approximated $0.6 million; the second greatest unrealized loss position approximated $0.2 million. The securities were evaluated for impairment as of December 31, 2012.
Each quarter, ProAssurance performs a detailed analysis for the purpose of assessing whether any of the securities it holds in an unrealized loss position have suffered an other-than-temporary impairment in value. A detailed discussion of the factors considered in the assessment is included in Note 1.
Fixed maturity securities held in an unrealized loss position at December 31, 2013, excluding asset-backed securities, have paid all scheduled contractual payments and are expected to continue doing so. Expected future cash flows of asset-backed securities held in an unrealized loss position were estimated as part of the December 31, 2013 impairment evaluation using the most recently available six-month historical performance data for the collateral (loans) underlying the security or, if historical data was not available, sector based assumptions, and equaled or exceeded the current amortized cost basis of the security.
Net Investment Income
Net investment income by investment category was as follows:
	Year Ended December 31
(In thousands)	2013			2012			2011
Fixed maturities	$	122,065		$	133,088		$	140,897
Equities	9,454			6,947			1,808
Short-term investments and Other invested assets	2,584			660			2,812
Business owned life insurance	1,960			2,008			2,017
Investment fees and expenses	(6,798		)	(6,609		)	(6,578		)
Net investment income	$	129,265		$	136,094		$	140,956
Net Realized Investment Gains (Losses)
The following table provides detailed information regarding net realized investment gains (losses):
	Year Ended December 31
(In thousands)	2013			2012				2011
Total other-than-temporary impairment losses:
State and municipal bonds	$	(71	)	$	—			$	—
Residential mortgage-backed securities	—			(557		)		(782		)
Corporate debt	—			(878		)		(505		)
Other investments	—			(131		)		(3,827		)
High yield asset-backed securities	—			—				(75		)
Portion recognized in (reclassified from) Other Comprehensive Income:
Residential mortgage-backed securities	—			(201		)		(823		)
Net impairment losses recognized in earnings	(71		)	(1,767		)		(6,012		)
Gross realized gains, available-for-sale securities	18,130			18,645				14,625
Gross realized (losses), available-for-sale securities	(7,031		)	(2,076		)		(1,754		)
Net realized gains (losses), trading securities	20,444			1,485				2,212
Change in unrealized holding gains (losses), trading securities	35,507			12,673				(3,188		)
Decrease (increase) in the fair value of liabilities carried at fair value	—			(1,245		)		111
Other	925			1,148				—
Net realized investment gains (losses)	$	67,904		$	28,863			$	5,994
No significant impairment losses were recognized during 2013. Significant impairment losses recognized during 2012 and 2011 were as follows:
•	ProAssurance recognized impairment losses related to certain residential mortgage-backed securities in 2012 and 2011 because carrying values for those securities were greater than the future cash flows expected to be received from the securities.
•	ProAssurance recognized impairments related to corporate debt securities in 2012 and 2011 because the credit standing of the issuers had deteriorated.
•	ProAssurance recognized impairments in 2012 and 2011 related to an interest in an LLC, accounted for using the cost method, that was classified as a part of Other Investments. In 2011, the LLC announced a plan to convert to a publicly traded investment fund, and OTTI was recognized in subsequent periods in order to carry the interest at the NAV reported by the fund. The conversion occurred in 2012.
The following table presents a roll forward of cumulative credit losses recorded in earnings related to impaired debt securities for which a portion of the other-than-temporary impairment was recorded in Other Comprehensive Income.
(In thousands)	2013			2012			2011
Balance January 1	$	3,301		$	5,870		$	4,446
Additional credit losses recognized during the period, related to securities for which:
OTTI has been previously recognized	—			268			1,424
Reductions due to:
Securities sold during the period (realized)	(3,218		)	(2,837		)	—
Balance December 31	$	83		$	3,301		$	5,870
Other information regarding sales and purchases of available-for-sale securities is as follows:
	Year Ended December 31
(In millions)	2013			2012			2011
Proceeds from sales (exclusive of maturities and paydowns)	$	593.3		$	500.2		$	424.8
Purchases	$	519.2		$	646.2		$	782.6

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Reinsurance	'
	Reinsurance
	ProAssurance has various excess of loss, quota share, and cession reinsurance agreements in place, with each agreement relating to the policies written during a specified coverage period, typically one year. Historically, the professional liability per claim retention level has varied between 90% and 100% of the first $1 million and up to 5% of claims exceeding those levels depending on the coverage year and the state in which business was written. Also, there are various fronting and quota share arrangements that apply to certain healthcare professional policies, generally those associated with a group of affiliated insureds or an insured with a large number of risk exposures. Gross and net written premium associated with such arrangements approximated $37.5 million and $20.2 million, respectively, during the year ended December 31, 2013. Medical technology and life sciences products coverages are separately reinsured, generally with 100% retention on the first $1 million of coverage and between 5% and 33% of coverage exceeding those levels, with additional loss participation if specified limits are exceeded. ProAssurance also insures professional and product liability risks that are above the limits of its basic reinsurance treaties. These risks are reinsured on a facultative basis, whereby the reinsurer agrees to insure a particular risk up to a designated limit.
	The effect of reinsurance on premiums written and earned was as follows (in thousands):
		2013 Premiums						2012 Premiums						2011 Premiums
		Written			Earned			Written			Earned			Written			Earned
	Direct	$	566,745		$	568,629		$	536,318		$	558,200		$	565,746		$	570,891
	Assumed	802			804			113			116			149			154
	Ceded	(42,365		)	(41,514		)	(8,133		)	(7,652		)	(7,388		)	(5,630		)
	Net premiums	$	525,182		$	527,919		$	528,298		$	550,664		$	558,507		$	565,415
	The receivable from reinsurers on unpaid losses and loss adjustment expenses represents Management’s estimate of amounts that will be recoverable under ProAssurance reinsurance agreements. Most Company reinsurance agreements base the amount of premium that is due to the reinsurer in part on losses reimbursed or to be reimbursed under the agreement, and may also reflect maximum and minimum amounts of ceded premium. Ceded premium amounts are estimated based on Management’s expectation of ultimate losses and the portion of those losses that are allocable to reinsurers according to the terms of the agreements, including any minimums or maximums. Given the uncertainty of the ultimate amounts of losses, Management’s estimates of losses and related amounts recoverable may vary significantly from the eventual outcome. During the years ended December 31, 2013, 2012 and 2011 ProAssurance reduced premiums ceded by $16.4 million, $34.3 million and $30.6 million, respectively, due to changes in Management’s estimates of amounts due to reinsurers related to prior accident year loss recoveries.
	Reinsurance contracts do not relieve ProAssurance from its obligations to policyholders and ProAssurance remains liable to its policyholders whether or not reinsurers honor their contractual obligations to ProAssurance. ProAssurance continually monitors its reinsurers to minimize its exposure to significant losses from reinsurer insolvencies.
	At December 31, 2013, $92.1 million of the total amounts due from reinsurers of $237.9 million (including receivables related to paid and unpaid losses and LAE and prepaid reinsurance premiums, less reinsurance premiums payable) was due from four reinsurers which had an individual balance which exceeded $20 million. Each of these reinsurers had an A.M. Best credit rating of A or above.
	At December 31, 2013 and 2012 ProAssurance had no allowance for credit losses related to its reinsurance receivables. During the years ended December 31, 2013, 2012 and 2011 no reinsurance balances were written off for credit reasons.
	At December 31, 2013, all reinsurance recoverables were considered collectible. Reinsurance recoverables totaling approximately $25 million were collateralized by letters of credit or funds withheld. At December 31, 2013 no amounts due from individual reinsurers exceeded 5% of shareholders’ equity.
	There were no significant reinsurance commutations in 2013 or 2012. During 2011, ProAssurance commuted (terminated) various outstanding reinsurance agreements for approximately $4.3 million in cash. The commutations reduced Receivable from Reinsurers on Paid Losses and Receivable from Reinsurers on Unpaid Losses, combined, by approximately $4.0 million (net of cash received) and reduced Reinsurance Premiums Payable by approximately $5.6 million.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Deferred income taxes reflect the net tax effects of temporary differences between the amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of ProAssurance’s deferred tax assets and liabilities were as follows:
	(In thousands)	2013			2012
	Deferred tax assets
	Unpaid loss discount	$	51,879		$	57,811
	Unearned premium adjustment	21,861			20,497
	Compensation related	18,172			14,634
	Intangibles	2,074			2,214
	Total deferred tax assets	93,986			95,156
	Deferred tax liabilities
	Deferred acquisition costs	10,150			8,112
	Unrealized gains on investments, net	32,127			78,284
	Fixed assets	4,166			5,630
	Basis differentials–investments	31,247			3,029
	Intangibles	13,238			14,311
	Other	1,301			375
	Total deferred tax liabilities	92,229			109,741
	Net deferred tax assets (liabilities)	$	1,757		$	(14,585	)
	At December 31, 2013, ProAssurance has no available net operating loss carryforwards, capital loss carryforwards, or Alternative Minimum Tax credit carryforwards. ProAssurance files income tax returns in the U.S. federal jurisdiction and various states.
	The IRS has concluded an examination of the 2009 and 2010 returns and has issued a Notice of Proposed Adjustment (NOPA) for these years which would increase ProAssurance's current tax liability by approximately $130 million. During 2013 ProAssurance submitted a comprehensive written protest to the IRS Office of Appeals regarding certain issues within the NOPA, all of which related to the timing of deductions. ProAssurance and the IRS have since reached a tentative settlement on the contested issues which will result in no additional tax liability for ProAssurance. Other non-contested issues addressed by the NOPA are expected to result in a net Federal income tax refund of approximately $9.6 million. ProAssurance believes that the tentative settlement with the IRS will be finalized during 2014.
	At December 31, 2013, ProAssurance had a receivable for federal income taxes of $27 million, which was carried as a part of Other Assets. ProAssurance had a payable for federal income taxes of $20 million at December 31, 2012, which was carried as a part of Other Liabilities.
	Except for the 2006 tax year, the statutes of limitation are closed for all years prior to 2009. The statutes for the 2006, 2009 and 2010 tax years have been extended until September 30, 2014.
	A reconciliation of the beginning and ending amounts of unrecognized tax benefits for 2013 and 2012 was as follows:
	(In thousands)	2013			2012			2011
	Balance at January 1	$	4,823		$	18,585		$	8,344
	(Decreases) for tax positions taken during the current year	—			(10,206		)	—
	Increases for tax positions taken during prior years	—			—			18,585
	(Decreases) for tax positions taken during prior years	—			(3,556		)	—
	(Decreases) relating to settlements with taxing authorities	—			—			(8,344		)
	Balance at December 31	$	4,823		$	4,823		$	18,585
	ProAssurance's provision for uncertain tax positions at both December 31, 2013 and December 31, 2012 related entirely to the timing of deductions. Changes to the provision recognized in current taxes in 2012 were offset by the recognition of a like but opposite change to deferred taxes. Unrecognized tax benefits at December 31, 2013, if recognized, would not affect the effective tax rate but would accelerate the payment of tax. As with any uncertain tax position, there is a possibility that the ultimate deduction recognized could differ from the provision established by ProAssurance. As the Company's uncertain tax positions relate to the timing of deductions, management expects the liability to fully reverse during the next twelve months.
	ProAssurance recognizes interest and/or penalties related to income tax matters in income tax expense. No interest was recognized in the income statement during the year ended December 31, 2013. Interest recognized during the years ended December 31, 2012 and 2011approximated $0.5 million and $0.8 million, respectively. The accrued liability for interest approximated $1.3 million and $1.4 million at December 31, 2013 and 2012, respectively.
	A reconciliation of “expected” income tax expense (35% of income before income taxes) to actual income tax expense in the accompanying financial statements follows:
	(In thousands)	2013			2012			2011
	Computed “expected” tax expense	$	139,005		$	138,588		$	145,109
	Tax-exempt income	(14,509		)	(14,374		)	(13,793		)
	Tax credits	(17,888		)	(10,005		)	(5,654		)
	Non-taxable gain on acquisition	(11,310		)	—			—
	Other	4,338			6,287			1,840
	Total	$	99,636		$	120,496		$	127,502

Deferred_Policy_Acquisition_Co

Deferred Policy Acquisition Costs	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Deferred Policy Acquisition Costs	'
	Deferred Policy Acquisition Costs
	Policy acquisition costs, most significantly commissions, premium taxes, and underwriting salaries and benefits, that are primarily and directly related to the successful production of new and renewal insurance contracts are capitalized as policy acquisition costs and amortized to expense as the related premium revenues are earned.
	Amortization of deferred policy acquisition costs was $59.1 million, $57.0 million and $59.6 million for the years ended December 31, 2013, 2012 and 2011, respectively.

Reserve_for_Losses_and_Loss_Ad

Reserve for Losses and Loss Adjustment Expenses	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Reserve for Losses and Loss Adjustment Expenses	'
	Reserve for Losses and Loss Adjustment Expenses
	The reserve for losses is established based on estimates of individual claims and actuarially determined estimates of future losses based on ProAssurance’s past loss experience, available industry data and projections as to future claims frequency, severity, inflationary trends and settlement patterns. Estimating reserves, and particularly liability reserves, is a complex process. Claims may be resolved over an extended period of time, often five years or more, and may be subject to litigation. Estimating losses for liability claims requires ProAssurance to make and revise judgments and assessments regarding multiple uncertainties over an extended period of time. As a result, reserve estimates may vary significantly from the eventual outcome. The assumptions used in establishing ProAssurance’s reserves are regularly reviewed and updated by management as new data becomes available. Changes to estimates of previously established reserves are included in earnings in the period in which the estimate is changed.
	ProAssurance believes that the methods it uses to establish reserves are reasonable and appropriate. Each year, ProAssurance uses internal actuaries to review the reserve for losses of each insurance subsidiary. ProAssurance also engages consulting actuaries to review ProAssurance claims data and provide observations regarding cost trends, rate adequacy and ultimate loss costs. ProAssurance considers the views of the actuaries as well as other factors, such as known, anticipated or estimated changes in frequency and severity of claims and loss retention levels and premium rates, in establishing the amount of its reserve for losses. The statutory filings of each insurance company with the insurance regulators must be accompanied by an external actuary's certification as to their respective reserves in accordance with the requirements of the NAIC.
	Activity in the reserve for losses and loss adjustment expenses is summarized as follows:
	(In thousands)	2013			2012			2011
	Balance, beginning of year	$	2,054,994		$	2,247,772		$	2,414,100
	Less reinsurance recoverables on unpaid losses and loss adjustment expenses	191,645			247,658			277,436
	Net balance, beginning of year	1,863,349			2,000,114			2,136,664
	Net reserves acquired from acquisitions	126,007			22,464			—
	Net losses:
	Current year	447,510			451,951			488,152
	Favorable development of reserves established in prior years, net	(222,749		)	(272,038		)	(325,865		)
	Total	224,761			179,913			162,287
	Paid related to:
	Current year	(43,616		)	(38,439		)	(34,240		)
	Prior years	(345,197		)	(300,703		)	(264,597		)
	Total paid	(388,813		)	(339,142		)	(298,837		)
	Net balance, end of year	1,825,304			1,863,349			2,000,114
	Plus reinsurance recoverables on unpaid losses and loss adjustment expenses	247,518			191,645			247,658
	Balance, end of year	$	2,072,822		$	2,054,994		$	2,247,772
	As discussed in Note 1, estimating liability reserves is complex and requires the use of many assumptions. As time passes and ultimate losses for prior years are either known or become subject to a more precise estimation, ProAssurance increases or decreases the reserve estimates established in prior periods. The favorable development recognized in 2013 primarily reflects a lower than anticipated claims severity trend for accident years 2005 through 2011. The favorable development recognized in 2012 and 2011 was primarily due to lower than anticipated claims severity trends for accident years 2004 through 2009 and accident years 2004 through 2008, respectively. Actuarial evaluations of both internal and industry actual claims data in 2013, 2012 and 2011 all indicated that claims severity (i.e. the average size of a claim) is increasing more slowly than was anticipated when the reserves for 2004 through 2009 were initially established.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	ProAssurance is involved in various legal actions related to insurance policies and claims handling including, but not limited to, claims asserted by policyholders. These types of legal actions arise in the Company’s ordinary course of business and, in accordance with GAAP for insurance entities, are considered as a part of the Company’s loss reserving process, which is described in detail under “Accounting Policies – Losses and Loss Adjustment Expenses” in Note 1.
	ProAssurance has funding commitments primarily related to non-public investment entities totaling approximately $164.2 million, expected to be paid as follows: $49.6 million in 2014, $68.9 million in 2015 and 2016 combined, $26.8 million in 2017 and 2018 combined, and $18.9 million thereafter.
	As a member of Lloyd's and a capital provider to Syndicate 1729 ProAssurance is required to provide capital, referred to as Funds at Lloyd's (FAL), to support Syndicate 1729. In order to meet these FAL requirements, ProAssurance, through a wholly owned subsidiary, provided a standby letter of credit (LOC) of £41.9 million ($69.3 million at December 31, 2013) and cash deposits of $8.7 million. At December 31, 2013 the LOC was fully secured by cash deposits, see Note 1. The LOC, unless earlier released by Lloyd's, expires four years from the date it is terminated or canceled. Any amounts advanced under the LOC will bear interest at prime plus 400 basis points or the highest legal rate for the borrowing. ProAssurance must pay a fee related to the LOC during the period it is outstanding, currently 50 basis points, which is to be re-determined annually based on ProAssurance’s then current credit standing and whether the LOC has been secured, with the maximum fee set at 188 basis points. No amounts have been drawn against the LOC at December 31, 2013.
	ProAssurance has also issued an unconditional revolving credit agreement (the Credit Agreement) of up to £10 million ($17 million at December 31, 2013) to the Premium Trust Fund of Syndicate 1729 for the purpose of providing working capital. Advances under the Credit Agreement bear interest at 8.5% annually, and are repayable upon demand after December 31, 2016. As of December 31, 2013, £1.0 million ($1.7 million) had been advanced under the agreement.
	ProAssurance is involved in a number of operating leases primarily for office space and office equipment. The following is a schedule of future minimum lease payments for operating leases that had initial or remaining non-cancelable lease terms in excess of one year as of December 31, 2013.
	Operating Leases
	(In thousands)
	2014	$	3,039
	2015	2,750
	2016	2,553
	2017	2,394
	Thereafter	9,175
	Total minimum lease payments	$	19,911
	ProAssurance incurred rent expense of $3.2 million, $2.7 million and $3.4 million in the years ended December 31, 2013, 2012 and 2011, respectively.

Longterm_Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Long-term Debt	'
	Long-term Debt
	ProAssurance’s outstanding long-term debt consisted of the following:
	(In thousands)	December 31,		December 31,
		2013		2012
	Senior notes due 2023, unsecured, interest at 5.3% annually	$	250,000	$	—
	Revolving credit agreement, expires in 2016	—		125,000
		$	250,000	$	125,000
	Senior Notes due 2023 (the Senior Notes)
	The Senior Notes are the unsecured obligations of ProAssurance Corporation, due in full in November 2023, unless sooner redeemed, with interest payable semiannually. Redemptions may be made prior to maturity, in whole or part, at the greater of par or the sum of the present values of the outstanding principal and remaining interest payments calculated at 40 basis points above the then-current rate for U.S. Treasury Notes with a term comparable to the remaining term of the Senior Notes. There are no financial covenants associated with the Senior Notes.
	Revolving Credit Agreement
	ProAssurance has entered into a revolving credit agreement (the “Agreement”) with five participating lenders with an expiration date of April 15, 2016. The Agreement permits ProAssurance to borrow, repay and reborrow from the lenders during the term of the Agreement; aggregate outstanding borrowings are not permitted to exceed $150 million at any time. All borrowings are required to be repaid prior to the expiration date of the Agreement. ProAssurance is required to pay a commitment fee, ranging from 15 to 30 basis points based on ProAssurance’s credit ratings, on the average unused portion of the credit line during the term of the Agreement. Borrowings under the agreement may be secured or unsecured and accrue interest at a selected base rate, adjusted by a margin, which can vary from 0 to 188 basis points, based on ProAssurance’s credit rating and whether the borrowing is secured or unsecured. The base rate selected may be the current one-, three- or six-month LIBOR rate, with the LIBOR term selected fixing the interest period for which the rate is effective. If LIBOR is not selected, the base rate defaults to the highest of (1) the Prime rate (2) the Federal Funds rate plus 50 basis points or (3) the one month LIBOR rate plus 100 basis points, determined daily. Rates are reset each successive interest period until the borrowing is repaid.
	The Agreement contains customary representations, covenants and events constituting default, and remedies for default. Additionally, the Agreement carries the following financial covenants:
	-1	ProAssurance is not permitted to have a leverage ratio of Consolidated Funded Indebtedness (principally, obligations for borrowed money, obligations evidenced by instruments such as notes or acceptances, standby and commercial Letters of Credit, and contingent obligations) to Consolidated Total Capitalization (principally, total non-trade liabilities on a consolidated basis plus consolidated shareholders’ equity, exclusive of accumulated other comprehensive income) greater than 0.35 to 1.0, determined at the end of each fiscal quarter.
	-2	ProAssurance is required to maintain a minimum net worth of not less than the sum of 75% of Consolidated Net Worth (consolidated shareholders’ equity, exclusive of accumulated other comprehensive income) at December 31, 2010, plus 50% of consolidated net income earned each fiscal quarter, if positive, beginning with the quarter ending March 31, 2011, plus 100% of net cash proceeds resulting from the issuance of ProAssurance capital stock.
	Funds borrowed under the terms of the Revolving Credit Agreement will be used for general corporate purposes, including, but not limited to, use as short-term working capital, funding for share repurchases as authorized by the Board, and for support of other activities ProAssurance enters into in the normal course of business.
	Covenant Compliance
	ProAssurance is currently in compliance with all covenants.
	Loss on Extinguishment
	ProAssurance recognized a $2.2 million loss on extinguishment of debt during the third quarter of 2012 upon repayment of a note payable carried at fair value.

Shareholders_Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Shareholders' Equity	'
	Shareholders’ Equity
	At December 31, 2013 and 2012, ProAssurance had 100 million shares of authorized common stock and 50 million shares of authorized preferred stock. The Board has the authority to determine provisions for the issuance of preferred shares, including the number of shares to be issued, the designations, powers, preferences and rights, and the qualifications, limitations or restrictions of such shares. To date, the Board has not approved the issuance of preferred stock.
	The Board has declared cash dividends quarterly since the third quarter of 2011. Initially, dividends were $0.125 per share but were increased to $0.25 per share in the fourth quarter of 2012 and increased to $0.30 per share in the fourth quarter of 2013. With the exception of the fourth quarter 2012 dividend which was accelerated and paid in December 2012, each quarterly dividend was paid in the month following the end of the quarter. The liability for unpaid dividends at December 31, 2013 of $18.4 million was included in other liabilities. The Board also declared and paid a special dividend of $2.50 per share during December 2012.
	ProAssurance's ability to pay dividends to its shareholders is limited by its holding company structure, to the extent of the net assets held by its insurance subsidiaries, as discussed in Note 16. Otherwise, there are no other regulatory restrictions on ProAssurance's retained earnings or net income that materially impact its ability to pay dividends. Based on Shareholders' Equity at December 31, 2013, total equity of $572 million was free of debt covenant restrictions regarding the payment of dividends. However, any decision to pay future cash dividends is subject to the Board’s final determination after a comprehensive review of financial performance, future expectations and other factors deemed relevant by the Board.
	As of December 31, 2013 Board authorizations for the repurchase of common shares or the retirement of outstanding debt of $202.6 million remained available for use. The timing and quantity of purchases depends upon market conditions and changes in ProAssurance's capital requirements and is subject to limitations that may be imposed on such purchases by applicable securities laws and regulations, and the rules of the New York Stock Exchange.
	ProAssurance repurchased 0.7 million common shares during both the years ended December 31, 2013 and 2011. ProAssurance did not repurchase any common shares during the year ended December 31, 2012. During the years ended December 31, 2013, 2012 and 2011 ProAssurance reissued approximately 25,000, 23,000 and 18,000 treasury shares, respectively, to participant accounts of the ProAssurance Corporation 2011 Employee Stock Ownership Plan. In December, 2012 treasury shares were reissued to provide 7.7 million of the shares needed for the two-for-one stock split effected December 27, 2012 in the form of a stock dividend.
	ProAssurance issued approximately 41,000, 37,000 and 40,000 common shares to employees in February 2013, 2012 and 2011, respectively, as bonus compensation, as approved by the Compensation Committee of the Board. The shares issued were valued at fair value (the market price of a ProAssurance common share on the date of award).
	As of December 31, 2013, approximately 3.0 million of ProAssurance's authorized common shares were reserved by the Board for award or issuance under the incentive compensation plans described in Note 12 and an additional 0.8 million of authorized common shares were reserved for the issuance of currently outstanding restricted share and performance share unit awards and for the exercise of outstanding stock options.
	Other Comprehensive Income (Loss) (OCI)
	For all periods presented, OCI was comprised of unrealized gains and losses arising during the period, less reclassification adjustments, related to available-for-sale securities, net of tax. At December 31, 2013 and 2012, accumulated other comprehensive income was comprised entirely of unrealized gains and losses from available-for-sale securities, including non-credit impairment losses previously recognized in OCI of $0.5 million and $0.9 million, respectively, net of tax. All tax effects were computed using a 35% rate.
	Amounts reclassified from accumulated other comprehensive income to net income during the years ended December 31, 2013, 2012 and 2011 all related to available-for-sale securities and included the following:
	(In thousands)	2013			2012			2011
	Reclassifications from accumulated other comprehensive income to net income, available for sale securities:
	Realized investment gains (losses)	$	11,375		$	17,350		$	13,101
	Non-credit impairment losses reclassified to earnings, due to sale of securities or reclassification as a credit loss	(347		)	(2,417		)	(2,415		)
	Total amounts reclassified, before tax effect	11,028			14,933			10,686
	Tax effect (at 35%)	(3,860		)	(5,227		)	(3,740		)
	Net reclassification adjustments	$	7,168		$	9,706		$	6,946

ShareBased_Payments

Share-Based Payments	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-Based Payments	'
	Share-Based Payments
	Share-based compensation costs are primarily classified as underwriting, policy acquisition and operating expenses.
	Since May 2013, ProAssurance has provided share-based compensation to employees under the ProAssurance Corporation Amended and Restated 2014 Equity Incentive Plan. Previously, compensation was provided under the ProAssurance Corporation 2008 Equity Incentive Plan (2009 to May 2013), the ProAssurance Corporation 2004 Equity Incentive Plan (2005 to 2008) and the ProAssurance Corporation Incentive Compensation Stock Plan (prior to 2005). The Compensation Committee of the Board is responsible for the administration of all four plans.
	ProAssurance has provided share-based compensation to employees utilizing four types of awards: stock options, restricted share units, performance share units and purchase match units. The following table provides a summary of compensation expense and compensation cost that will be charged to expense in future periods, by award type, and the total related tax benefit recognized during each period.
		Share-Based										Unrecognized Compensation Cost
		Compensation Expense
		Year Ended December 31										31-Dec-13
		2013			2012			2011				Amount				Remaining
																Recognition Period
		(In millions)										(In millions)				(Weighted average years)
	Stock Options	$	—		$	—		$	0.1			$	—			N/A
	Restricted Share Units	1.6			1.6			1.3				2.1				1.7
	Performance Share Units	7.1			6.7			5.6				8.1				1.7
	Purchase Match Units	0.5			0.3			0.1				1.5				2.2
	Total share-based compensation expense	$	9.2		$	8.6		$	7.1			$	11.7
	Tax benefit recognized	$	3.2		$	3		$	2.5
	All awards are charged to expense as an increase to equity over the service period (generally the vesting period) associated with the award. Except for stock options, which are separately described below, awards vest in their entirety at the end of a three-year period following the grant date based on a continuous service requirement and, for performance share units, achievement of a performance objective. Partial vesting is permitted for retirees. A ProAssurance common share is issued for each restricted, performance or purchase match unit once vesting requirements are met, except that units sufficient to satisfy required tax withholdings are paid in cash.
	On December 27, 2012 ProAssurance paid a special dividend of $2.50 per common share and effected a two-for-one split. Thereafter, the Compensation Committee adjusted outstanding awards and options so as to put award holders in the same economic position after the split and dividend as before. No compensation resulted from the adjustments because there was no change to the intrinsic value of the awards. The following tables reflect award activity as if the adjustments had occurred at the beginning of the earliest period presented.
	Stock Options
	ProAssurance’s stock options generally vested in five equal installments, the first installment occurring six months after the grant date and the other installments occurring annually thereafter. All options were granted with an exercise price equal to the market price of a ProAssurance common share on the date of grant, and an original term of ten years. ProAssurance option agreements permit cashless exercise whereby the exercise price and any required tax withholdings are allowed to be satisfied by the retention of shares that would otherwise be deliverable to the option holder. ProAssurance issues new shares for options exercised.
	Activity for stock options during 2013, 2012 and 2011 is summarized below.
		2013					2012							2011
		Options		Weighted			Options			Weighted				Options			Weighted
				Average						Average							Average
				Exercise						Exercise							Exercise
				Price						Price							Price
	Outstanding, beginning of year	20,302		$	23.15		1,014,661			$	22.76			1,430,105			$	21.85
	Granted	—		—			—			—				—			—
	Exercised	(2,220	)	24.28			(994,148	)		22.75				(412,695	)		19.61
	Forfeited or expired	—		—			(211	)		25.67				(2,749	)		25.36
	Outstanding at end of year	18,082		23			20,302			23.15				1,014,661			22.76
	Exercisable at end of year	18,082		23			20,302			23.15				959,889			22.59
	Outstanding at end of year,	18,082		23			20,302			23.15				1,014,064			22.75
	vested or expected to vest
	All options were vested as of December 31, 2012. The aggregate grant date fair value of options vested during the years ended December 31, 2012 and 2011 was $0.9 million and $0.9 million, respectively. The aggregate intrinsic value of options exercised during 2013, 2012 and 2011 was $0.1 million, $19.8 million and $5.8 million, respectively. ProAssurance outstanding options had an aggregate intrinsic value of $0.5 million and a weighted average remaining contractual term of 2.93 years at December 31, 2013. There were no cash proceeds from options exercised during the years ended December 31, 2013, 2012 or 2011.
	Restricted Share Units
	Activity for restricted share units during 2013, 2012 and 2011 is summarized below. Grant date fair values are based on the market value of a ProAssurance common share on the date of grant.
		2013					2012							2011
		Units		Weighted			Units			Weighted				Units			Weighted
				Average						Average							Average
				Grant Date						Grant Date							Grant Date
				Fair Value						Fair Value							Fair Value
	Beginning non-vested balance	157,212		$	31.94		167,236			$	25.52			120,478			$	23.88
	Granted	39,400		46.97			51,864			42.22				52,256			29.27
	Forfeited	(603	)	35.91			(2,823	)		35.23				(5,075	)		25.38
	Vested and released	(57,239	)	25.25			(59,065	)		22.61				(423	)		22.56
	Ending non-vested balance	138,770		38.92			157,212			31.94				167,236			25.52
	The aggregate grant date fair value of restricted share units vested and released in 2013 and 2012 totaled $1.4 million and $1.3 million respectively. The aggregate intrinsic value of restricted share units vested and released in 2013 and 2012 (including units paid in cash to cover tax withholdings) totaled $2.7 million and $2.6 million, respectively.
	Performance Share Units
	Performance share units vest only if minimum performance objectives are met, and the number of units earned varies from 75% to 125% of a base award depending upon the degree to which stated performance objectives are achieved. Performance share unit activity for 2013, 2012 and 2011 is summarized below. The table reflects the base number of units; actual awards that vest depends upon the extent to which performance objectives are achieved. Grant date fair values are based on the market value of a ProAssurance common share on the date of grant.
		2013					2012							2011
		Base Units		Weighted			Base Units			Weighted				Base Units			Weighted
				Average						Average							Average
				Grant Date						Grant Date							Grant Date
				Fair Value						Fair Value							Fair Value
	Beginning non-vested balance	552,417		$	33.21		522,599			$	26.36			493,661			$	24.56
	Granted	145,580		46.97			212,205			42.22				196,186			30.3
	Forfeited	(17,043	)	38.9			(20,492	)		31.44				(15,804	)		26.28
	Vested and released	(194,274	)	26.39			(161,895	)		23.13				(151,444	)		25.61
	Ending non-vested balance	486,680		39.86			552,417			33.21				522,599			26.36
	Common shares issued due to vesting of awards	135,044					114,884							112,822
	The aggregate grant date fair value of performance share units (base level) vested and released in 2013, 2012 and 2011 totaled $5.1 million, $3.7 million and $3.9 million, respectively. The aggregate intrinsic value of performance share units vested and released in 2013, 2012 and 2011 (including units paid in cash to cover tax withholdings) totaled $9.1 million, $7.2 million and $5.3 million, respectively. The vested units were issued at the maximum level (125%) based on performance levels achieved.
	Purchase Match Units
The ProAssurance Corporation 2011 Employee Stock Ownership Plan (the 2011 Plan) began operating effective January 1, 2011. The 2011 Plan provides a purchase match unit for each share purchased with contributions by eligible plan participants, limited to $5,000 annually per participant.
Purchase match unit activity during 2013, 2012 and 2011 is summarized below. Grant date fair values are based on the market value of a ProAssurance common share on the date of grant.
	2013					2012							2011
	Units		Weighted			Units			Weighted				Units			Weighted
			Average						Average							Average
			Grant  Date						Grant  Date							Grant  Date
			Fair Value						Fair Value							Fair Value
Beginning non-vested balance	40,985		$	39.85		18,900			$	36.2			—			$	—
Granted	25,151		43.57			23,799			42.59				19,016			36.2
Forfeited	(2,456	)	40.71			(1,610	)		37.72				(116	)		36.2
Vested and released	(555	)	36.33			(104	)		36.2				—			—
Ending non-vested balance	63,125		41.34			40,985			39.85				18,900			36.2

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2013
Variable Interest Entities [Abstract]	'
Variable Interest Entities	'
	Variable Interest Entities
	ProAssurance holds passive interests in a number of entities that are considered to be Variable Interest Entities (VIEs) under GAAP guidance. ProAssurance's VIE interests principally consist of interests in LPs/LLCs formed for the purpose of achieving diversified equity and debt returns. ProAssurance VIE interests carried as a part of Other Investments totaled $27.3 million at December 31, 2013 and $25.1 million at December 31, 2012. ProAssurance VIE interests, carried as a part of Investment in Unconsolidated Subsidiaries, totaled $49.5 million at December 31, 2013 and $33.7 million at December 31, 2012.
	ProAssurance has not consolidated these VIE's because it has either very limited or no power to control the activities that most significantly affect the economic performance of these entities and is not the primary beneficiary of any of the entities. ProAssurance’s involvement with each entity is limited to its direct ownership interest in the entity. ProAssurance has no arrangements or agreements of significance with any of the entities to provide other financial support to or on behalf of the entity. At December 31, 2013, ProAssurance’s maximum loss exposure relative to these investments was limited to the carrying value of ProAssurance’s investment in the VIE.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Earnings Per Share
	Diluted weighted average shares is calculated as basic weighted average shares plus the effect, calculated using the treasury stock method, of assuming that dilutive stock options have been exercised and that performance, restricted, and purchase share units have vested. All outstanding stock options, performance, restricted, and purchase share units had a dilutive effect for the years ended December 31, 2013, 2012 and 2011.

Benefit_Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Benefit Plans	'
	Benefit Plans
	ProAssurance maintains a defined contribution savings and retirement plan (the ProAssurance Savings Plan) that is intended to provide retirement income to eligible employees. The plan provides for employer contributions to the plan of between 5% and 10% of salary for qualified employees. During 2013 and 2011, ProAssurance also maintained similar plans of acquired entities prior to the plans being merged into the ProAssurance Savings Plan. ProAssurance incurred expense related to the savings and retirement plans of $9.8 million, $5.1 million and $4.3 million during the years ended December 31, 2013, 2012 and 2011, respectively.
	ProAssurance also maintains a non-qualified deferred compensation plan (the ProAssurance Plan) that allows participating management employees to defer a portion of their current salary. ProAssurance incurred expense related to the ProAssurance Plan of $0.2 million during each of the years ended December 31, 2013, 2012 and 2011. ProAssurance deferred compensation liabilities totaled $13.1 million at December 31, 2013 and $11.1 million at December 31, 2012. The liabilities included amounts due under the ProAssurance Plan and amounts due under individual agreements with current or former employees.

Statutory_Accounting_and_Divid

Statutory Accounting and Dividend Restrictions	12 Months Ended
	Dec. 31, 2013
Statutory Accounting And Dividend Restrictions [Abstract]	'
Statutory Accounting and Dividend Restrictions	'
	Statutory Accounting and Dividend Restrictions
	ProAssurance’s insurance subsidiaries are required to file statutory financial statements with state insurance regulatory authorities, prepared based upon statutory accounting practices prescribed or permitted by regulatory authorities. ProAssurance did not use any prescribed or permitted statutory accounting practices that differed from the National Association of Insurance Commissioners' statutory accounting practices at December 31, 2013, 2012 or 2011. Differences between net income prepared in accordance with GAAP and statutory net income are principally due to: (a) policy acquisition and certain software and equipment costs which are deferred under GAAP but expensed for statutory purposes and (b) certain deferred income taxes which are recognized under GAAP but are not recognized for statutory purposes.
	The NAIC specifies risk-based capital requirements for property and casualty insurance providers. At December 31, 2013 actual statutory capital and surplus for each of ProAssurance’s insurance subsidiaries substantially exceeded the regulatory requirements. Net earnings and capital and surplus of ProAssurance’s insurance subsidiaries on a statutory basis are shown in the following table. The table does not include Eastern, as the acquisition occurred on January 1, 2014 (see Note 18).
	(In millions)
	Statutory Net Earnings			Statutory Capital and Surplus
	2013	2012	2011	2013	2012
	$256	$312	$291	$1,642	$1,499
	At December 31, 2013 $1.8 billion of ProAssurance's consolidated net assets were held at its insurance subsidiaries, of which approximately $243 million are permitted to be paid as dividends over the course of 2014 without prior approval of state insurance regulators. However, the payment of any dividend requires prior notice to the insurance regulator in the state of domicile and the regulator may prevent the dividend if, in its judgment, payment of the dividend would have an adverse effect on the capital and surplus of the insurance subsidiary.

Quarterly_Results_of_Operation

Quarterly Results of Operations (unaudited)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Data [Abstract]	'
Quarterly Results of Operations (unaudited)	'
	Quarterly Results of Operations (unaudited)
	The following is a summary of unaudited quarterly results of operations for 2013 and 2012:
			2013
	(In thousands, except per share data)		1st			2nd			3rd			4th
	Net premiums earned		$	134,578		$	130,352		$	133,598		$	129,392
	Net losses and loss adjustment expenses:
	Current year		110,726			109,109			110,987			116,689
	Prior year		(53,100		)	(38,500		)	(49,350		)	(81,799		)
	Net income		112,850			50,451			63,357			70,864
	Basic earnings per share*		1.83			0.82			1.02			1.15
	Diluted earnings per share*		1.82			0.81			1.02			1.14
			2012
	(In thousands, except per share data)		1st			2nd			3rd			4th
	Net premiums earned		$	136,659		$	131,266		$	127,125		$	155,615
	Net losses and loss adjustment expenses:
	Current year		117,656			108,134			106,621			119,539
	Prior year		(47,457		)	(60,050		)	(50,000		)	(114,531		)
	Net income		55,645			58,453			60,106			101,266
	Basic earnings per share*		0.91			0.95			0.98			1.65
	Diluted earnings per share*		0.9			0.95			0.97			1.64
	*	Quarterly and year-to-date computations of per share amounts are made independently; therefore, the sum of per share amounts for the quarters may not equal per share amounts for the respective year-to-date periods.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	As discussed in Note 2, on January 1, 2014 ProAssurance completed the acquisition of Eastern. Funds required for the purchase were transferred to a third party agent on December 27, 2013 and distributed to eligible Eastern shareholders subsequent to the completion of the transaction.

Schedule_I_Summary_of_Investme

Schedule I - Summary of Investments-Other Than Investments In Related Parties	12 Months Ended
	Dec. 31, 2013
Summary of Investments, Other than Investments in Related Parties [Abstract]	'
Schedule I - Summary of Investments Other than Investments in Related Parties	'
	Type of Investment	Recorded		Fair		Amount Which is
		Cost		Value		Presented
		Basis				in the
						Balance Sheet
	(In thousands)
	Fixed Maturities
	Bonds:
	U.S. Government or government agencies and authorities	$	197,057	$	203,482	$	203,482
	States, municipalities and political subdivisions	1,116,060		1,154,666		1,154,666
	Foreign Governments	5,141		5,348		5,348
	Public utilities	95,943		98,501		98,501
	All other corporate bonds	1,220,604		1,250,311		1,250,311
	Certificates of deposit	150		6,993		6,993
	Mortgage-backed securities	391,301		398,748		398,748
	Total Fixed Maturities	3,026,256		3,118,049		3,118,049
	Equity Securities, available-for-sale
	Common Stocks:
	Banks, trusts and insurance companies	—		—		—
	Total Equity Securities, available-for-sale	—		—		—
	Equity Securities, trading
	Common Stocks:
	Public utilities	5,880		7,107		7,107
	Banks, trusts and insurance companies	68,596		81,536		81,536
	Industrial, miscellaneous and all other	128,832		164,898		164,898
	Total Equity Securities, trading	203,308		253,541		253,541
	Other long-term investments	320,850		317,816		320,850
	Short-term investments	248,605		248,605		248,605
	Total Investments	$	3,799,019	$	3,938,011	$	3,941,045

Schedule_II_Condensed_Financia

Schedule II - Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2013
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Schedule II - Condensed Financial Information of Registrant	'
	ProAssurance Corporation – Registrant Only
	Condensed Balance Sheets
		December 31
	(In thousands)	2013			2012
	Assets
	Investment in subsidiaries, at equity	$	2,005,420		$	2,092,445
	Fixed maturities available for sale, at fair value	86,603			249,318
	Equity securities, trading, at fair value	12,043			10,487
	Short-term investments	191,991			4,366
	Cash and cash equivalents	37,459			29,397
	Restricted cash	78,000			—
	Due from subsidiaries	3,315			23,708
	Other assets	255,313			7,747
	Total Assets	$	2,670,144		$	2,417,468
	Liabilities and Shareholders’ Equity
	Liabilities:
	Other liabilities	$	25,730		$	21,888
	Long-term debt	250,000			125,000
	Total Liabilities	275,730			146,888
	Shareholders’ Equity:
	Common stock	621			619
	Other shareholders’ equity, including unrealized gains (losses) on securities of subsidiaries	2,393,793			2,269,961
	Total Shareholders’ Equity	2,394,414			2,270,580
	Total Liabilities and Shareholders’ Equity	$	2,670,144		$	2,417,468
	ProAssurance Corporation – Registrant Only
	Condensed Statements of Income
		Year Ended December 31
	(In thousands)	2013			2012			2011
	Net investment income	$	5,789		$	5,281		$	1,582
	Equity in earnings (loss) of unconsolidated subsidiaries	—			(728		)	(2,479		)
	Net realized investment gains (losses)	5,334			3,230			(141		)
	Other income (loss)	170			54			101
		11,293			7,837			(937		)
	Expenses:
	Interest expense	2,747			1,534			1,833
	Other expenses	13,213			8,870			7,855
		15,960			10,404			9,688
	Income (loss) before income tax expense (benefit) and equity in net income of consolidated subsidiaries	(4,667		)	(2,567		)	(10,625		)
	Income tax expense (benefit)	(1,007		)	773			(3,209		)
	Income (loss) before equity in net income of consolidated subsidiaries	(3,660		)	(3,340		)	(7,416		)
	Equity in net income of consolidated subsidiaries	301,183			278,810			294,512
	Net income	$	297,523		$	275,470		$	287,096
	ProAssurance Corporation – Registrant Only
	Condensed Statements of Cash Flow
		Year Ended December 31
	(In thousands)	2013			2012			2011
	Net cash provided (used) by operating activities	$	(26,319	)	$	3,601		$	(3,982	)
	Investing activities
	Purchases of equity securities trading	(1,265		)	(364		)	(990		)
	Proceeds from sale or maturities of:
	Fixed maturities, available for sale	224,993			150,192			19,398
	Equity securities trading	1,113			616			6,887
	Net decrease (increase) in short-term investments	(187,625		)	58,657			(28,708		)
	Dividends from subsidiaries	239,484			59,369			90,020
	Contribution of capital to subsidiaries	—			(184,330		)	(12,500		)
	Deposit made for future acquisition	(205,244		)	—			—
	(Increase) decrease in restricted cash	(78,000		)	—			—
	Funding for Syndicate 1729	(8,699		)	—			—
	Other	(20		)	(1		)	(3,070		)
	Net cash provided (used) by investing activities	(15,263		)	84,139			71,037
	Financing activities
	Proceeds from long-term debt	250,000			125,000			—
	Principal repayment of debt	(125,000		)	(32,992		)	—
Repurchase of common stock	(29,089		)	—			(21,005		)
Subsidiary payments for common shares and share-based compensation awarded to subsidiary employees	6,258			7,066			6,071
Excess of tax benefit from share-based payment arrangements	2,128			7,022			1,711
Dividends to shareholders	(46,375		)	(200,118		)	(7,617		)
Other	(8,278		)	(12,259		)	(2,561		)
Net cash provided (used) by financing activities	49,644			(106,281		)	(23,401		)
Increase (decrease) in cash and cash equivalents	8,062			(18,541		)	43,654
Cash and cash equivalents, beginning of period	29,397			47,938			4,284
Cash and cash equivalents, end of period	$	37,459		$	29,397		$	47,938
Significant non-cash transactions:
Securities transferred at fair value as dividends from subsidiaries	$	69,011		$	241,081		$	197,224
Notes to Condensed Financial Statements of Registrant
1. Basis of Presentation
The registrant-only financial statements should be read in conjunction with ProAssurance Corporation’s (PRA Parent) consolidated financial statements. At December 31, 2013 and 2012, PRA Parent’s investment in subsidiaries is stated at the initial consolidation value plus equity in the undistributed earnings of subsidiaries since the date of acquisition.
2. Business Combinations
On January 1, 2013, ProAssurance, through a wholly owned subsidiary, completed the acquisition of Medmarc Mutual Insurance Company, now Medmarc Casualty Insurance Company (Medmarc), through a sponsored demutualization. A gain recognized on the acquisition is included in the December 31, 2013 Consolidated Statements of Income and Comprehensive Income.
On January 1, 2014, ProAssurance completed the acquisition of Eastern Insurance Holdings, Inc. (Eastern) (NASDAQ: EIHI) by purchasing 100% of its outstanding common shares. ProAssurance acquired Eastern for cash of $205 million. ProAssurance transferred all of the cash required to complete the transaction to a third-party agent for the benefit of Eastern eligible shareholders on December 27, 2013; the deposit was classified as a part of Other Assets at December 31, 2013.
Additional information regarding business combinations is provided in Note 2 of the Notes to Consolidated Financial Statements.
3. Other Assets
At December 31, 2013 Other assets was principally comprised of a $205 million deposit made related to the Eastern transaction, discussed in Note 2 above.
4. Long-term Debt
Outstanding long-term debt, as of December 31, 2013 and 2012, consists of the following:
(In thousands)	2013			2012
Senior notes due 2023, unsecured, interest at 5.3% annually	$	250,000		$	—
Revolving credit agreement, expires in 2016	—			125,000
	$	250,000		$	125,000
See Note 10 of the Notes to Consolidated Financial Statements included herein for a detailed description of the terms of the Senior Notes due 2023 and the Revolving Credit Agreement.
5. Related Party Transactions
PRA Parent received dividends from its subsidiaries of $308.5 million, $300.5 million and $287.2 million during the years ended December 31, 2013, 2012 and 2011, respectively. PRA Parent did not contribute capital to its subsidiaries during the year ended December 31, 2013 and contributed capital of $184.3 million and $12.5 million during the years ended December 31, 2012 and 2011, respectively. Capital contributed in 2012 was primarily for the purpose of funding the Medmarc acquisition.
6. Income Taxes
Under terms of PRA Parent’s tax sharing agreement with its subsidiaries, income tax provisions for individual companies are allocated on a separate company basis.
7. Transactions with Syndicate 1729
As a member of Lloyd's and a capital provider to Syndicate 1729 ProAssurance is required to provide capital, referred to as Funds at Lloyd's (FAL), to support Syndicate 1729. In order to meet these FAL requirements, ProAssurance, through a wholly owned subsidiary, provided a standby letter of credit of £41.9 million ($69.3 million at December 31, 2013) and cash deposits of $8.7 million. At December 31, 2013 the LOC was fully secured by cash deposits of PRA Parent, shown separately on the registrant-only Condensed Balance Sheet as Restricted cash. ProAssurance also has a revolving credit agreement (the Credit Agreement) with Syndicate 1729 to provide operating funds of up to £10 million (approximately $17 million at December 31, 2013). At December 31, 2013, £1.0 million ($1.7 million) had been drawn under the Credit Agreement. Both the required funded capital and the funds drawn under the Credit Agreement were classified as a part of Other assets at December 31, 2013. See Note 9 of the Notes to Consolidated Financial Statements for more information regarding transactions with Syndicate 1729.

Schedule_III_Supplementary_Ins

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2013
Supplementary Insurance Information [Abstract]	'
Schedule III - Supplementary Insurance Information	'
	(In thousands)	2013			2012			2011
	Deferred policy acquisition costs	$	28,999		$	23,179		$	26,626
	Reserve for losses and loss adjustment expenses	2,072,822			2,054,994			2,247,772
	Unearned premiums	256,255			233,861			251,155
	Net premiums earned	527,919			550,664			565,415
	Net investment income	129,265			136,094			140,956
	Losses and loss adjustment expenses incurred related to current year, net of reinsurance	447,510			451,951			488,152
	Losses and loss adjustment expenses incurred related to prior year, net of reinsurance	(222,749		)	(272,038		)	(325,865		)
	Paid losses and loss adjustment expenses, net of reinsurance	388,813			339,142			298,837
	Underwriting, policy acquisition and operating expenses:
	Amortization of deferred policy acquisition costs	59,063			57,007			59,591
	Other underwriting, policy acquisition and operating expenses	88,754			78,624			76,830
	Net premiums written	525,182			528,298			558,507
	Note: all amounts above are derived entirely from consolidated property and casualty entities.

Schedule_IV_Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2013
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]	'
Schedule IV - Reinsurance	'
	(In thousands)		2013			2012			2011
	Property and Liability (1)
	Premiums earned		$	568,629		$	558,200		$	570,891
	Premiums ceded		(41,514		)	(7,652		)	(5,630		)
	Premiums assumed		804			116			154
	Net premiums earned		$	527,919		$	550,664		$	565,415
	Percentage of amount assumed to net		0.15		%	0.02		%	0.03		%
	-1	All of ProAssurance’s premiums are related to property and liability coverages.

Accounting_Policies_Policies

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Organization and Nature of Business	'
	Organization and Nature of Business
	ProAssurance Corporation (ProAssurance, PRA or the Company), a Delaware corporation, is an insurance holding company for wholly owned specialty property and casualty insurance companies that principally provide professional liability insurance for healthcare professionals and facilities, professional liability insurance for attorneys, liability insurance for medical technology and life sciences risks and, effective January 1, 2014, workers' compensation insurance. ProAssurance is also the majority capital provider for Syndicate 1729 at Lloyd's of London (Syndicate 1729) which began writing a range of property and casualty insurance and reinsurance lines effective January 1, 2014. During the years ended December 31, 2013, 2012 and 2011 ProAssurance primarily operated in the United States of America (U.S.) in a single reportable segment.
Principles of Consolidation	'
	Principles of Consolidation
	The accompanying consolidated financial statements include the accounts of ProAssurance Corporation and its wholly-owned subsidiaries. Investments in entities where ProAssurance holds a greater than minor interest but does not hold a controlling interest are accounted for using the equity method. All significant intercompany accounts and transactions are eliminated in consolidation.
Basis of Presentation	'
	Basis of Presentation
	The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and disclosures related to these amounts at the date of the financial statements. Actual results could differ from those estimates.
Stock Split	'
	Stock Split
	In 2012, the Board of Directors of ProAssurance Corporation (the Board) declared a two-for-one split of ProAssurance common shares which was effected December 27, 2012 in the form of a stock dividend. All share and per share information provided in this report reflects the effect of the split for all periods presented.
Gain on Acquisition	'
	Gain on Acquisition
	The year-end deferred tax review resulted in a $3.7 million reduction of the Gain on acquisition recorded for our acquisition of Medmarc. Certain deferred tax liabilities relating to unrealized gains on investments held by Medmarc were not established as a part of the assets acquired and liabilities assumed for Medmarc and as a result the value of the net assets acquired in the transaction were overstated. An adjustment was made to the Gain on acquisition in the fourth quarter of 2013 reducing the gain from $36.0 million to $32.3 million. The adjustment was not quantitatively or qualitatively material to the prior or current period presented.
Recognition of Revenues	'
	Recognition of Revenues
	Insurance premiums are recognized as revenues pro rata over the terms of the policies, which are principally one year in duration.
	At December 31, 2013 and 2012 ProAssurance had established allowances for credit losses related to premium and agency receivables (classified as a part of Other Assets) as follows:
	(in thousands)		Premium			Agency
			Receivables			Receivables
	Allowance for credit losses:
	Balance at December 31, 2011		$	990		$	332
	Estimated credit losses		157			—
	Account write offs, net of recoveries		(147		)	(46		)
	Balance at December 31, 2012		1,000			286
	Estimated credit losses		236			—
	Account write offs, net of recoveries		(246		)	(236		)
	Balance at December 31, 2013		$	990		$	50
Losses and Loss Adjustment Expenses	'
	Losses and Loss Adjustment Expenses
	ProAssurance establishes its reserve for losses and loss adjustment expenses ("reserve for losses" or "reserve") based on estimates of the future amounts necessary to pay claims and expenses associated with the investigation and settlement of claims. The reserve for losses is determined on the basis of individual claims and payments thereon as well as actuarially determined estimates of future losses based on past loss experience, available industry data and projections as to future claims frequency, severity, inflationary trends, judicial trends, legislative changes and settlement patterns.
	Management establishes the reserve for losses after taking into consideration a variety of factors including the conclusions reached by internal actuaries, premium rates, claims frequency, historical paid and incurred loss development trends, the effect of inflation, general economic trends, the legal and political environment, and the reports received from consulting actuaries. Internal actuaries perform an in-depth review of the reserve for losses at least semi-annually using the loss and exposure data of ProAssurance subsidiaries. Management engages consulting actuaries to review subsidiary loss and exposure data and provide reports to Management regarding the adequacy of reserves.
	Estimating casualty insurance reserves, and particularly long-tailed insurance reserves, is a complex process. Long-tailed insurance is characterized by the extended period of time between collecting the premium for insuring a risk and the ultimate payment of losses. For ProAssurance the period of time required to resolve claims is often five years or more, and claims may be subject to litigation. Estimating losses for long-tailed insurance claims requires ProAssurance to make and revise judgments and assessments regarding multiple uncertainties over an extended period of time. As a result, reserve estimates may vary significantly from the eventual outcome. Reserve estimates and the assumptions on which these estimates are predicated are regularly reviewed and updated as new information becomes available. Any adjustments necessary are reflected in then current operations. Due to the size of ProAssurance’s reserve for losses, even a small percentage adjustment to these estimates could have a material effect on earnings in the period in which the adjustment is made, as was the case in 2013, 2012 and 2011.
	The effect of adjustments made to reinsured losses is mitigated by the corresponding adjustment that is made to reinsurance recoveries. Thus, in any given year, ProAssurance may make significant adjustments to gross losses that have little effect on its net losses.
Reinsurance Receivables	'
	Reinsurance Receivables
	ProAssurance enters into reinsurance agreements whereby other insurance entities agree to assume a portion of the risk associated with the policies issued by ProAssurance. In return, ProAssurance agrees to pay a premium to the reinsurer. ProAssurance purchases reinsurance to provide for greater diversification of business and to allow management to control exposure to potential losses arising from large risks.
	Receivable from Reinsurers on Paid Losses is the estimated amount of losses already paid that will be recoverable from reinsurers. Receivable from Reinsurers on Unpaid Losses is the estimated amount of future loss payments that will be recoverable from reinsurers. Reinsurance Recoveries are the portion of losses incurred during the period that are estimated to be allocable to reinsurers. Premiums ceded are the estimated premiums that will be due to reinsurers with respect to premiums earned and losses incurred during the period.
	These estimates are based upon management’s estimates of ultimate losses and the portion of those losses that are allocable to reinsurers under the terms of the related reinsurance agreements. Given the uncertainty of the ultimate amounts of losses, these estimates may vary significantly from the eventual outcome. Management regularly reviews these estimates and any adjustments necessary are reflected in the period in which the estimate is changed. Due to the size of the receivable from reinsurers, even a small adjustment to the estimates could have a material effect on ProAssurance’s results of operations for the period in which the change is made.
	Reinsurance contracts do not relieve ProAssurance from its obligations to policyholders. ProAssurance continually monitors its reinsurers to minimize its exposure to significant losses from reinsurer insolvencies. Any amount determined to be uncollectible is written off in the period in which the uncollectible amount is identified.
Investments	'
	Investments
	Fair Values
	Fair values of investment securities are primarily provided by independent pricing services. The pricing services provide an exchange traded price, if available, or provide an estimated price determined using multiple observable inputs, including exchange traded prices for similar assets. Management reviews valuations of securities obtained from the pricing services for accuracy based upon the specifics of the security, including class, maturity, credit rating, durations, collateral, and comparable markets for similar securities. Multiple observable inputs are not available for certain of our investments, including municipal bonds and corporate debt not actively traded, and investments in limited partnerships/limited liability companies (LPs/LLCs). Management values these municipal bonds and corporate debt either using a single non-binding broker quote or pricing models that utilize market based assumptions that have limited observable inputs. Management values investments in LPs/LLCs based on the net asset value of the interest held, as provided by the fund.
	Fixed Maturities and Equity Securities
	Fixed maturities and equity securities are considered as either available-for-sale or trading securities.
	Available-for-sale securities are carried at fair value, determined as described above, and unrealized gains and losses on such available-for-sale securities are included, net of related tax effects, in Shareholders’ Equity as a component of Accumulated Other Comprehensive Income (Loss).
	Investment income includes amortization of premium and accretion of discount related to available-for-sale debt securities acquired at other than par value. Debt securities and mandatorily redeemable preferred stock with maturities beyond one year when purchased are classified as fixed maturities.
	Trading portfolio securities are carried at fair value, determined as described above, with the holding gains and losses included in realized investment gains and losses in the current period.
	Short-term Investments
	Short-term investments, which have a maturity at purchase of one year or less, are primarily comprised of investments in U.S. Treasury obligations and commercial paper. All balances are reported at amortized cost, which approximates fair value.
	Other Investments
	Investments in LPs/LLCs where ProAssurance has virtually no influence over the operating and financial policies of an investee are accounted for using the cost method. Under the cost method, investments are valued at cost, with investment income recognized when received.
	Investment in Unconsolidated Subsidiaries
	Investments in LPs/LLCs where ProAssurance is deemed to have influence because it holds a greater than a minor interest are accounted for using the equity method. Under the equity method, the recorded basis of the investment is adjusted each period for the investor’s pro rata share of the investee’s income or loss. Investments in unconsolidated subsidiaries include tax credit partnerships accounted for using the equity method, whereby ProAssurance’s proportionate share of income or loss is included in investment income. Tax credits received from the partnerships are recognized in the period received as a reduction to current tax expenses.
	Business Owned Life Insurance (BOLI)
	ProAssurance owns life insurance contracts on certain management employees. The life insurance contracts are carried at their current cash surrender value. Changes in the cash surrender value are included in income in the current period as investment income. Death proceeds from the contracts are recorded when the proceeds become payable under the policy terms.
	Realized Gains and Losses
	Realized investment gains and losses are recognized on the specific identification basis.
	Other-than-temporary Impairments
	ProAssurance evaluates its available-for-sale investment securities on at least a quarterly basis for the purpose of determining whether declines in fair value below recorded cost basis represent other-than-temporary declines. The assessment of whether the amortized cost basis of debt securities, particularly asset-backed debt securities, is expected to be recovered requires management to make assumptions regarding various matters affecting cash flows to be received in the future. The choice of assumptions is subjective and requires the use of judgments; actual credit losses experienced in future periods may differ from management’s estimates of those credit losses.
	If there is intent to sell the security or if it is more likely than not that the security will be required to be sold before full recovery of its amortized cost basis, ProAssurance considers a decline in fair value to be an other-than-temporary impairment. Otherwise, ProAssurance considers the following factors in determining whether an investment’s decline is other-than-temporary:
	For equity securities:
	•	the length of time for which the fair value of the investment has been less than its recorded basis;
	•	the financial condition and near-term prospects of the issuer underlying the investment, taking into consideration the economic prospects of the issuer’s industry and geographical region, to the extent that information is publicly available;
	•	the historical and implied volatility of the fair value of the security;
	For debt securities, an evaluation is made as to whether the decline in fair value is due to credit loss, which is defined as the excess of the current amortized cost basis of the security over the present value of expected future cash flows. Methodologies used to estimate the present value of expected cash flows to determine if a decline is due to a credit loss are:
	•	For non-structured fixed maturities (U.S. Treasury securities, obligations of U.S. Government and government agencies and authorities, obligations of states, municipalities and political subdivisions, and corporate debt) the estimate of expected cash flows is determined by projecting a recovery value and a recovery time frame and assessing whether further principal and interest will be received. ProAssurance considers the following in projecting recovery values and recovery time frames:
	•	third party research and credit rating reports;
	•	the current credit standing of the issuer, including credit rating downgrades, whether before or after the balance sheet date;
	•	internal assessments and the assessments of external portfolio managers regarding specific circumstances surrounding an investment, which indicate the investment is more or less likely to recover its amortized cost than other investments with a similar structure;
	•	failure of the issuer of the security to make scheduled interest or principal payments;
	•	For structured securities (primarily asset-backed securities), ProAssurance estimates the present value of the security’s cash flows using the effective yield of the security at the date of acquisition (or the most recent implied rate used to accrete the security if the implied rate has changed as a result of a previous impairment or changes in expected cash flows). ProAssurance considers the most recently available six month averages of the levels of delinquencies, defaults, severities, and prepayments for the collateral (loans) underlying the securitization or, if historical data is not available, sector based assumptions, to estimate expected future cash flows of these securities.
	Investments in LPs/LLCs are evaluated for impairment by comparing ProAssurance’s carrying value to net asset value (NAV) of ProAssurance’s interest in the fund as reported by the fund manager. Additionally, Management considers the performance of the fund relative to the market, the stated objectives of the fund, and cash flows expected from the fund and fund audit reports, if available.
	Investments in tax credit partnerships are evaluated for OTTI by considering both qualitative and quantitative factors which include: whether cash flows currently expected from the investment, primarily tax benefits, equal or exceed the carrying value of the investment, whether currently expected cash flows are less than those expected at the time the investment was acquired, and ProAssurance's ability and intent to hold the investment until the recovery of its carrying value.
	ProAssurance recognizes other than temporary impairments, including impairments of debt securities due to credit loss, in earnings as a part of net realized investment gains (losses). In subsequent periods, any measurement of gain or loss or impairment is based on the revised amortized basis of the security. Declines in fair value, including impairments of debt securities that are not evaluated as being due to credit loss, not considered to be other-than-temporary are recognized in other comprehensive income.
	Asset-backed securities that have been impaired due to credit or are below investment grade quality are accounted for under the effective yield method. Under the effective yield method estimates of cash flows expected over the life of asset-backed securities are then used to recognize income on the investment balance for subsequent accounting per
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	For purposes of the consolidated balance sheets and statements of cash flow, ProAssurance considers all demand deposits and overnight investments to be cash equivalents.
Restricted Cash	'
	Restricted Cash
	Restricted cash represents cash balances which are not available for immediate or general use. At December 31, 2013 ProAssurance's Restricted cash was comprised entirely of a deposit collateralizing a standby letter of credit entered into as a part of our funding at Lloyd's.
Deferred Policy Acquisition Costs	'
	Deferred Policy Acquisition Costs
	Costs that vary with and are directly related to the successful production of new and renewal premiums (primarily premium taxes, commissions and underwriting salaries) are deferred to the extent they are recoverable against unearned premiums and are amortized as related premiums are earned.
Income Taxes/Deferred Taxes	'
	Income Taxes/Deferred Taxes
	ProAssurance files a consolidated federal income tax return. Tax-related interest and penalties are recognized as components of tax expense.
	ProAssurance evaluates tax positions taken on tax returns and recognizes positions in the financial statements when it is more likely than not that the position will be sustained upon resolution with a taxing authority. If recognized, the benefit is measured as the largest amount of benefit that has a greater than fifty percent probability of being realized. Uncertain tax positions are reviewed each period by considering changes in facts and circumstances, such as changes in tax law, interactions with taxing authorities and developments in case law, and adjustments are made as considered necessary. Adjustments to unrecognized tax benefits may affect income tax expense and the settlement of uncertain tax positions may require the use of cash.
	Deferred federal income taxes arise from the recognition of temporary differences between the basis of assets and liabilities determined for financial reporting purposes and the basis determined for income tax purposes. ProAssurance’s temporary differences principally relate to loss reserves, unearned premium, deferred policy acquisition costs, unrealized investment gains (losses), basis differentials for investments, compensation accruals, and intangibles. Deferred tax assets and liabilities are measured using the enacted tax rates expected to be in effect when such benefits are realized. ProAssurance reviews its deferred tax assets quarterly for impairment. If management determines that it is more likely than not that some or all of a deferred tax asset will not be realized, a valuation allowance is recorded to reduce the carrying value of the asset. In assessing the need for a valuation allowance, management is required to make certain judgments and assumptions about the future operations of ProAssurance based on historical experience and information as of the measurement period regarding reversal of existing temporary differences, carryback capacity, future taxable income, including its capital and operating characteristics, and tax planning strategies.
	Changes in tax laws and rates could also affect recorded deferred tax assets and liabilities in the future. Management is not aware of any such changes that would have a material effect on the Company’s results of operations, cash flows or financial position.
Real Estate	'
	Real Estate
	Real Estate balances are reported at cost or, for properties acquired in business combinations, estimated fair value on the date of acquisition, less accumulated depreciation. Real estate principally consists of properties in use as corporate offices. Depreciation is computed over the estimated useful lives of the related property using the straight-line method. Excess office capacity is leased or made available for lease; rental income is included in other income and real estate expenses are included in underwriting, policy acquisition and operating expenses.
	Real estate accumulated depreciation was approximately $21.6 million and $20.2 million at December 31, 2013 and 2012, respectively. Real estate depreciation expense for the years ended December 31, 2013, 2012 and 2011 was $1.5 million, $1.4 million and $1.7 million, respectively.
Intangible Assets	'
	Intangible Assets
	Intangible assets with definite lives are amortized over the estimated useful life of the asset. Amortizable intangible assets primarily consist of renewal rights and agency relationships and had a carrying value of $51.7 million and $50.2 million at December 31, 2013 and 2012, respectively. Intangible assets with an indefinite life, primarily state licenses, are not amortized and had carrying values of $16.8 million and $14.3 million at December 31, 2013 and 2012, respectively. Increases in both amortizable and non-amortizable intangible assets during 2013 were attributable to intangible assets recognized related to 2013 business combinations. Intangible assets are evaluated for impairment on an annual basis.
	Accumulated amortization of intangible assets was $16.5 million and $11.2 million at December 31, 2013 and 2012, respectively. Amortization expense for intangible assets for the three years ended December 31, 2013, 2012 and 2011 was $5.3 million, $4.5 million and $4.7 million, respectively. Aggregate amortization expense for intangible assets, excluding amortizable intangible assets recorded through our acquisition of Eastern, is estimated to be $5.1 million for 2014, $3.1 million for 2015, $2.8 million for 2016, $2.8 million for 2017 and $2.4 million for 2018.
Goodwill	'
	Goodwill
	ProAssurance makes at least an annual assessment as to whether the value of its goodwill assets are impaired. Management evaluates the carrying value of goodwill annually on October 1 and before the annual evaluation if events occur or circumstances change that would more likely than not reduce the fair value below the carrying value. Because ProAssurance operates in a single operating segment and all components within the segment are economically similar, ProAssurance is considered a single reporting unit for the purposes of the impairment evaluation. In assessing goodwill, Management estimates the fair value of the reporting unit on the evaluation date based on the Company’s market capitalization and an expected premium that would be paid to acquire control of the Company (a control premium) and performs a sensitivity analysis using a range of historical stock prices and control premiums. Management concluded in 2013, 2012 and 2011 that the fair value of the Company’s reporting unit exceeded the carrying value and no adjustment to impair goodwill was necessary.
	Goodwill is recognized in conjunction with acquisitions as the excess of the purchase consideration for the acquisition over the fair value of identifiable assets acquired and liabilities assumed. The fair value of identifiable assets and liabilities, and thus goodwill, is subject to redetermination within a measurement period of up to one year following completion of an acquisition. During 2013 goodwill was reduced by $1.9 million primarily related to the after-tax effect of the re-determination of the fair value of the reserve for losses associated with a business combination completed in late 2012.
Treasury Shares	'
	Treasury Stock
	Treasury shares are reported at cost, and are reflected on the balance sheets as an unallocated reduction of total equity.
Share-Based Payments	'
	Share-Based Payments
	ProAssurance recognizes compensation cost for share-based payments (including stock options, performance share units, restricted share units, and purchase match units) using the modified prospective method whereby the methodology for recognizing compensation expense differs depending upon the grant date of each share-based payment award. Compensation cost for awards is recognized based on the grant-date fair value of the award over the relevant service period of the award; for awards that vest in increments (graded vesting), compensation cost is recognized over the relevant service period for each separately vested portion of the award. Excess tax benefits (tax deductions realized in excess of the compensation costs recognized for the exercise of the awards, multiplied by the incremental tax rate) are reported as financing cash inflows.
Subsequent Events	'
	Subsequent Events
	In connection with its preparation of the Consolidated Financial Statements, ProAssurance has evaluated events that occurred subsequent to December 31, 2013, for recognition or disclosure in its financial statements and notes to the financial statements.
Accounting Changes	'
	Accounting Changes Adopted
	Intangibles-Goodwill and Other
	Effective for fiscal years beginning after September 15, 2012, the Financial Accounting Standards Board (FASB) revised guidance related to impairment testing of indefinite-lived intangible assets. The new guidance permits an entity to assess qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that an indefinite-lived intangible asset is impaired. Quantitative impairment testing is required only if the assessment of qualitative factors indicates it is more likely than not that impairment exists. ProAssurance adopted the guidance on January 1, 2013. Adoption of this guidance had no material effect on ProAssurance's results of operations or financial position.
	Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
	Effective for interim and annual reporting periods beginning after December 15, 2012, the FASB revised guidance related to the disclosure of amounts reclassified out of accumulated other comprehensive income. The most significant provisions of the new guidance require entities to present additional disclosure, either on the face of the income statement or in the notes, regarding significant amounts reclassified, in their entirety, from accumulated other comprehensive income to net income. ProAssurance adopted the guidance on January 1, 2013. Adoption of this guidance had no material effect on ProAssurance’s results of operations or financial position as it impacts disclosures only.
	Disclosures About Offsetting Assets and Liabilities
	Effective for fiscal years beginning on or after January 1, 2013, the FASB revised guidance related to disclosures about certain assets and liabilities in an entity’s financial statements. The guidance requires disclosures related to the net and gross positions of certain financial instruments and transactions that are either eligible for offset in accordance with existing GAAP guidance or subject to an agreement that requires such offset. The guidance must be applied retrospectively for all prior periods presented. ProAssurance adopted the guidance on January 1, 2013. Adoption of this guidance had no material effect on ProAssurance’s results of operations or financial position as it impacts disclosures only.
	Accounting for Costs Associated with Acquiring or Renewing Insurance Contracts
	Effective for fiscal years beginning after December 15, 2011, the FASB revised guidance regarding the interpretation of which costs relating to the acquisition of new or renewal insurance contracts qualify for deferral. The guidance permits deferral of qualifying costs only when associated with successful contract acquisitions. Internal selling agent and underwriter salary and benefit costs allocated to unsuccessful contracts, as well as advertising costs, are excluded. The guidance permitted but did not require retrospective application. ProAssurance prospectively adopted the guidance on January 1, 2012. Adoption of this guidance had no material effect on ProAssurance’s results of operations or financial position.
	Accounting Changes Not Yet Adopted
	Investments-Equity Method and Joint Ventures-Accounting for Investments in Qualified Affordable Housing Projects
	Effective for fiscal years beginning after December 15, 2014, the FASB issued guidance which permits qualified reporting entities to use a new accounting method, the proportional amortization method, for investments in qualified affordable housing projects. Under the new method the initial cost of an investment is amortized in proportion to the tax benefits received, and investment performance is recognized as a component of income tax expense (benefit) rather than as a component of investment income. ProAssurance is in the process of evaluating the effect that the use of the new method would have on its results of operations and financial position and whether it meets the qualification requirements for using the new method. ProAssurance plans to adopt the guidance beginning January 1, 2015.
	Liabilities-Obligations Resulting from Joint and Several Liability Arrangements
	Effective for fiscal years beginning after December 15, 2013, the FASB revised guidance related to obligations resulting from joint and several liability arrangements. The new guidance requires an entity to recognize, measure and disclose obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date, except for obligations already addressed within existing GAAP guidance, with retrospective application required for such arrangements existing at the beginning of the fiscal year of adoption. ProAssurance plans to adopt the guidance beginning January 1, 2014. Adoption of this guidance is expected to have no effect on ProAssurance's results of operations or financial position.
	Income Taxes-Presentation of Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
	Effective for fiscal years beginning after December 15, 2013, the FASB issued guidance related to the financial statement presentation of unrecognized tax benefits. The new guidance requires an entity to present unrecognized tax benefits as a reduction to a deferred tax asset resulting from a net operating loss carryforward, a similar tax loss, or tax credit carryforward except in circumstances where the relevant taxing authority does not permit offset or does not require offset and the entity does not intend to use the deferred tax asset for offset. The guidance requires prospective application for all unrecognized tax benefits that exist as of the effective date, but may be applied retrospectively. ProAssurance plans to adopt the guidance prospectively beginning January 1, 2014. Adoption of this guidance is expected to have no effect on ProAssurance's results of operations or financial position.

Accounting_Policies_Tables

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Summary of allowances for credit losses related to premium and agency receivables	'
	At December 31, 2013 and 2012 ProAssurance had established allowances for credit losses related to premium and agency receivables (classified as a part of Other Assets) as follows:
	(in thousands)	Premium			Agency
		Receivables			Receivables
	Allowance for credit losses:
	Balance at December 31, 2011	$	990		$	332
	Estimated credit losses	157			—
	Account write offs, net of recoveries	(147		)	(46		)
	Balance at December 31, 2012	1,000			286
	Estimated credit losses	236			—
	Account write offs, net of recoveries	(246		)	(236		)
	Balance at December 31, 2013	$	990		$	50

Business_Combinations_Tables

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Purchase Price Allocation	'
	The purchase consideration for Medmarc was allocated to the assets acquired and liabilities assumed based on their estimated fair values on the acquisition date, as shown in the table below. The purchase consideration was less than the estimated fair value of the net assets acquired resulting in a gain on the acquisition of $32.3 million, which reflects a reduction of $3.7 million recorded in the fourth quarter of 2013, as discussed in Note 1. ProAssurance believes it was able to acquire Medmarc for less than the fair value of its net assets due to Medmarc's declining premium base and its small capital position relative to other insurers in the medical technology and life sciences products liability insurance market.
	(In thousands)
	Fixed maturities, available for sale		$	269,529
	Equity securities, trading		30,976
	Cash and short-term investments		24,008
	Other investments		5,340
	Premiums receivable		2,986
	Receivable from reinsurers on paid and unpaid losses and LAE		73,107
	Intangible assets		3,630
	Other assets		14,614
	Reserve for losses and loss adjustment expenses		(201,072		)
	Unearned premiums		(16,937		)
	Deferred tax liabilities		(4,934		)
	Other liabilities		(15,233		)
	Fair value of net assets acquired		$	186,014
	Gain on Acquisition		(32,314		)
	Total purchase consideration		$	153,700
ProAssurance Consolidated results	'
	The following table provides Pro Forma Consolidated Results for the years ended December 31, 2013 and 2012 as if the Medmarc transaction had occurred on January 1, 2012. Pro Forma Consolidated Results reflect ProAssurance Actual Consolidated Results adjusted by the following, net of related tax effects:
	•	For the year ended December 31, 2012, the ProAssurance 2012 Actual Consolidated Results did not include Medmarc, and have been adjusted to include Medmarc's 2012 operating results. ProAssurance Actual Consolidated Results for the year ended December 31, 2013 included Medmarc operating results (Revenue of $46.5 million and Net Income of $15.7 million).
	•	Certain costs included in ProAssurance Actual Consolidated Results for the year ended December 31, 2013 have been reported in the Pro Forma Consolidated Results as if the costs had been incurred for the year ended December 31, 2012. Such costs include direct transaction costs and certain compensation costs directly related to the integration of Medmarc operations.
	•	Prior to the acquisition date, Medmarc reported on a statutory basis and expensed policy acquisition costs associated with successful contracts as incurred. After the acquisition date, in accordance with GAAP, Medmarc policy acquisition costs associated with successful contracts were capitalized and amortized to expense as the related premium revenues were earned, but no amortization was recognized for Medmarc policies written prior to the acquisition date. The Pro Forma Consolidated Results for both 2013 and 2012 have been adjusted to reflect policy acquisition costs as if Medmarc had followed GAAP guidance for these costs in pre-acquisition periods.
	•	Earnings for the year ended December 31, 2012 were reduced to reflect amortization of intangible assets and debt security premiums and discounts recorded as a part of the Medmarc purchase price allocation.
	•	The non-taxable gain on the acquisition of $32.3 million that was included in ProAssurance Actual Consolidated Results for the year ended December 31, 2013 has been reported in the Pro Forma Consolidated Results as being recognized during the year ended December 31, 2012.
		Year Ended December 31, 2013				Year Ended December 31, 2012
	(In thousands)	ProAssurance		ProAssurance		ProAssurance	ProAssurance
		Pro Forma		Actual		Pro Forma	Actual
		Consolidated		Consolidated Results		Consolidated	Consolidated Results
		Results				Results
	Revenue	$740,178		$740,178		$757,240	$715,854
	Net Income	$263,820		$297,523		$317,097	$275,470

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Assets and liabilities measured at fair value	'
	Fair values of assets measured at fair value on a recurring basis as of December 31, 2013 and December 31, 2012, including financial instruments for which ProAssurance has elected fair value, are shown in the following tables. The tables also indicate the fair value hierarchy of the valuation techniques utilized to determine those fair values. For some assets, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. When this is the case, the asset is categorized based on the level of the most significant input to the fair value measurement. Assessments of the significance of a particular input to the fair value measurement requires judgment and consideration of factors specific to the assets being valued.
		31-Dec-13
		Fair Value Measurements Using											Total
	(In thousands)	Level 1				Level 2				Level 3			Fair Value
	Assets:
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	—			$	170,714			$	—		$	170,714
	U.S. Government-sponsored enterprise obligations	—				32,768				—			32,768
	State and municipal bonds	—				1,147,328				7,338			1,154,666
	Corporate debt, multiple observable inputs	—				1,346,977				—			1,346,977
	Corporate debt, limited observable inputs:
	Other corporate debt, NRSRO ratings available	—				—				11,449			11,449
	Other corporate debt, NRSRO ratings not available	—				—				2,727			2,727
	Residential mortgage-backed securities	—				235,614				—			235,614
	Agency commercial mortgage-backed securities	—				27,475				—			27,475
	Other commercial mortgage-backed securities	—				61,390				—			61,390
	Other asset-backed securities	—				67,455				6,814			74,269
	Equity securities
	Financial	81,536				—				—			81,536
	Utilities/Energy	32,350				—				—			32,350
	Consumer oriented	66,461				—				—			66,461
	Industrial	57,262				—				—			57,262
	All other	15,932				—				—			15,932
	Short-term investments	248,605				—				—			248,605
	Financial instruments carried at fair value, classified as a part of:
	Investment in unconsolidated subsidiaries	—				—				72,062			72,062
	Total assets	$	502,146			$	3,089,721			$	100,390		$	3,692,257
		31-Dec-12
		Fair Value Measurements Using											Total
	(In thousands)	Level 1				Level 2				Level 3			Fair Value
	Assets:
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	—			$	205,857			$	—		$	205,857
	U.S. Government-sponsored enterprise obligations	—				56,947				—			56,947
	State and municipal bonds	—				1,212,804				7,175			1,219,979
	Corporate debt, multiple observable inputs	—				1,455,333				—			1,455,333
	Corporate debt, limited observable inputs:
	Private placement senior notes	—				—				346			346
	Other corporate debt, NRSRO ratings available	—				—				13,835			13,835
	Other corporate debt, NRSRO ratings not available	—				—				1,010			1,010
	Residential mortgage-backed securities	—				289,850				—			289,850
	Agency commercial mortgage-backed securities	—				59,464				—			59,464
	Other commercial mortgage-backed securities	—				74,106				—			74,106
	Other asset-backed securities	—				67,237				4,035			71,272
	Equity securities
	Financial	70,900				—				—			70,900
	Utilities/Energy	31,383				—				—			31,383
	Consumer oriented	51,100				—				—			51,100
	Industrial	29,695				—				—			29,695
	All other	19,540				—				—			19,540
	Short-term investments	59,761				11,976				—			71,737
	Financial instruments carried at fair value, classified as a part of:
	Investment in unconsolidated subsidiaries	—				—				33,739			33,739
	Total assets	$	262,379			$	3,433,574			$	60,140		$	3,756,093
Investments in Limited liability companies and limited partnerships	'
	Investment in unconsolidated subsidiaries consist of limited partnership (LP) and limited liability company (LLC) interests valued using the NAV provided by the LP/LLC, which approximates the fair value of the interest.
	Such interests include the following:
		Unfunded	Fair Value
		Commitments
	(In thousands)	December 31,	December 31,				December 31,
		2013	2013				2012
	Investments in LPs/LLCs:
	Secured debt fund (1)	$27,000	$	13,233			$	—
	Long equity fund (2)	None	6,574				—
	Long/Short equity funds (3)	None	28,385				17,115
	Non-public equity funds (4)	87,603	23,870				16,624
			$	72,062			$	33,739
	-1	The LP is structured to provide income and capital appreciation primarily through investments in senior secured debt. Redemptions are not allowed. Income and capital are to be periodically distributed at the discretion of the LP over an anticipated time frame that spans from 7 to 9 years.
	-2	The LP holds long equities of public international companies. Redemptions are allowed at the end of any calendar month with a prior notice requirement of 15 days and are paid within 10 days of the end of the calendar month of the redemption request.
	-3	Comprised of interests in two unrelated LP funds, each holds primarily long and short U.S. and North American equities, and targets absolute returns using a strategy designed to take advantage of event-driven market opportunities. One LP allows redemption with a notice requirement of up to 45 days with the redemption payable within 30 days of the redemption date, unless the redemption request is for 90% or more of the requestor’s capital balance. Redemptions at the 90% and above level will be paid at 90%, with the remainder paid after the LP’s annual audit. The other LP generally allows redemption of substantially all the capital semi-annually with 30 days notice.
	-4	Comprised of interests in three unrelated LP funds, each structured to provide capital appreciation through diversified investments in private equity, which can include investments in buyout, venture capital, mezzanine debt, distressed debt and other private equity-oriented LPs. One LP allows redemption by special consent; the others do not permit redemption. Income and capital are to be periodically distributed at the discretion of the LP over time frames that are anticipated to span from 4 to 12 years.
Summary of quantitative information about Level 3 fair value measurements	'
	Quantitative Information Regarding Level 3 Valuations
	Quantitative Information about Level 3 Fair Value Measurements
			Fair Value at
	(In millions)		31-Dec-13		31-Dec-12		Valuation Technique		Unobservable Input		Range
											(Weighted Average)
	Assets:
	State and municipal bonds		$7.30		$7.20		Market Comparable		Comparability Adjustment		0% - 10% (5%)
							Securities
							Discounted Cash Flows		Comparability Adjustment		0% - 10% (5%)
	Corporate debt with limited observable inputs		$14.20		$15.20		Market Comparable		Comparability Adjustment		0% - 5% (2.5%)
							Securities
							Discounted Cash Flows		Comparability Adjustment		0% - 5% (2.5%)
	Other asset-backed securities		$6.80		$4.00		Market Comparable		Comparability Adjustment		0% - 5% (2.5%)
							Securities
							Discounted Cash Flows		Comparability Adjustment		0% - 5% (2.5%)
Summary of changes in the fair value of assets measured at fair value	'
	The following tables (the Level 3 Tables) present summary information regarding changes in the fair value of assets measured at fair value using Level 3 inputs.
		31-Dec-13
		Level 3 Fair Value Measurements – Assets
	(In thousands)	State and Municipal Bonds				Corporate Debt				Asset-backed Securities			Investment in Unconsolidated Subsidiaries			Other Investments			Total
	Balance December 31, 2012	$	7,175			$	15,191			$	4,035		$	33,739		$	—		$	60,140
	Total gains (losses) realized and unrealized:
	Included in earnings, as a part of:
	Net investment income	—				(103		)		(17		)	—			—			(120		)
	Equity in earnings of unconsolidated subsidiaries	—				—				—			6,877			—			6,877
	Net realized investment gains (losses)	(44		)		(69		)		—			—			—			(113		)
	Included in other comprehensive income	1				(725		)		(61		)	—			—			(785		)
	Purchases	—				9,470				1,356			24,567			—			35,393
	Sales	(2,106		)		(1,629		)		(18		)	(14,632		)	—			(18,385		)
	Transfers in	2,312				2,114				3,800			21,511			—			29,737
	Transfers out	—				(10,073		)		(2,281		)	—			—			(12,354		)
	Balance December 31, 2013	$	7,338			$	14,176			$	6,814		$	72,062		$	—		$	100,390
	Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	$	—			$	—			$	—		$	6,877		$	—		$	6,877
		31-Dec-12
		Level 3 Fair Value Measurements – Assets
	(In thousands)	State and Municipal Bonds				Corporate Debt				Asset-backed Securities			Investment in Unconsolidated Subsidiaries			Other Investments			Total
	Balance December 31, 2011	$	7,200			$	8,082			$	—		$	23,841		$	15,873		$	54,996
	Total gains (losses) realized and unrealized:
	Included in earnings, as a part of:
	Net investment income	—				14				—			—			—			14
	Equity in earnings of unconsolidated subsidiaries	—				—				—			278			—			278
	Net realized investment gains (losses)	—				10				—			—			(131		)	(121		)
	Included in other comprehensive income	—				611				35			—			—			646
	Purchases	—				3,136				6,734			11,008			—			20,878
	Sales	(25		)		(1,951		)		(1,118		)	(1,388		)	—			(4,482		)
	Transfers in	—				9,220				—			—			—			9,220
	Transfers out	—				(3,931		)		(1,616		)	—			(15,742		)	(21,289		)
	Balance December 31, 2012	$	7,175			$	15,191			$	4,035		$	33,739		$	—		$	60,140
	Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	$	—			$	—			$	—		$	278		$	(131	)	$	147
Summary of changes in the fair value of liabilities measured at fair value	'
	The following table presents information for the year ended December 31, 2012 regarding liabilities for which ProAssurance had elected fair value treatment at December 31, 2011 and during 2012.
		31-Dec-12
		Level 3 Fair Value Measurements - Liabilities
	(In thousands)	2019 Note Payable				Interest rate swap agreement				Total
	Balance December 31, 2011	$	14,180			$	4,659			$	18,839
	Total (gains) losses realized and unrealized:
	Included in earnings as a part of:
	Net realized investment (gains) losses	769				476				1,245
	Loss on extinguishment of debt	2,163				—				2,163
	Settlements	(17,112		)		(5,135		)		(22,247		)
	Balance December 31, 2012	$	—			$	—			$	—
	Change in unrealized (gains) losses included in earnings for the above period for Level 3 liabilities outstanding at period-end	$	—			$	—			$	—
Financial instruments not measured at fair value	'
	The following table provides the estimated fair value of our financial instruments that, in accordance with GAAP for the type of investment, are measured using a methodology other than fair value. All fair values provided fall within the Level 3 fair value category.
		31-Dec-13								31-Dec-12
	(In thousands)	Carrying				Fair				Carrying			Fair
		Value				Value				Value			Value
	Financial assets:
	BOLI	$	54,374			$	54,374			$	31,085		$	38,656
	Investment in unconsolidated subsidiaries	142,174				139,548				87,310			91,528
	Other investments	52,240				51,833				52,414			52,414
	Other assets	17,940				17,940				11,400			11,385
	Financial liabilities:
	Senior notes due 2023	$	250,000			$	262,500			$	—		$	—
	Revolving credit agreement	—				—				125,000			125,000
	Other liabilities	13,303				13,303				12,130			12,085

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'
Amortized cost and estimated fair value of available-for-sale fixed maturities and equity securities	'
	Available-for-sale securities at December 31, 2013 and December 31, 2012 included the following:
		31-Dec-13
	(In thousands)	Amortized			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
		Cost
	Fixed maturities
	U.S. Treasury obligations	$	166,115		$	6,118			$	(1,519	)		$	170,714
	U.S. Government-sponsored enterprise obligations	30,942			2,251				(425		)		32,768
	State and municipal bonds	1,116,060			46,533				(7,927		)		1,154,666
	Corporate debt	1,321,838			53,059				(13,744		)		1,361,153
	Residential mortgage-backed securities	230,861			7,608				(2,855		)		235,614
	Agency commercial mortgage-backed securities	27,268			343				(136		)		27,475
	Other commercial mortgage-backed securities	59,066			2,491				(167		)		61,390
	Other asset-backed securities	74,106			487				(324		)		74,269
		$	3,026,256		$	118,890			$	(27,097	)		$	3,118,049
		31-Dec-12
	(In thousands)	Amortized			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
		Cost
	Fixed maturities
	U.S. Treasury obligations	$	191,642		$	14,266			$	(51	)		$	205,857
	U.S. Government-sponsored enterprise obligations	52,110			4,837				—				56,947
	State and municipal bonds	1,134,744			85,329				(94		)		1,219,979
	Corporate debt	1,375,880			96,187				(1,543		)		1,470,524
	Residential mortgage-backed securities	272,990			17,070				(210		)		289,850
	Agency commercial mortgage-backed securities	57,234			2,255				(25		)		59,464
	Other commercial mortgage-backed securities	69,062			5,049				(5		)		74,106
	Other asset-backed securities	70,670			1,203				(601		)		71,272
		3,224,332			226,196				(2,529		)		3,447,999
Schedule of available for sale securities by contractual maturity	'
	The recorded amortized cost basis and estimated fair value of available-for-sale fixed maturities at December 31, 2013, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
	(In thousands)	Amortized			Due in one				Due after				Due after			Due after		Total Fair
		Cost			year or less				one year				five years			ten years		Value
									through				through
									five years				ten years
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	166,115		$	15,501			$	107,433			$	44,102		$	3,678	$	170,714
	U.S. Government-sponsored enterprise obligations	30,942			3,226				21,564				7,759			219		32,768
	State and municipal bonds	1,116,060			57,081				406,444				467,219			223,922		1,154,666
	Corporate debt	1,321,838			124,080				578,894				627,496			30,683		1,361,153
	Residential mortgage-backed securities	230,861																235,614
	Agency commercial mortgage-backed securities	27,268																27,475
	Other commercial mortgage-backed securities	59,066																61,390
	Other asset-backed securities	74,106																74,269
		$	3,026,256															$	3,118,049
Other Investments	'
	Other Investments at December 31, 2013 and December 31, 2012 was comprised as follows:
	(In thousands)	December 31,			December 31,
		2013			2012
	Investments in LPs/LLCs, at cost	$	47,258		$	25,092
	FHLB capital stock, at cost	3,449			4,278
	Other, principally an annuity, at amortized cost	1,533			1,715
		$	52,240		$	31,085
Unconsolidated Subsidiaries	'
	ProAssurance holds investments in unconsolidated subsidiaries, accounted for under the equity method. The investments include the following:
		31-Dec-13						Carrying Value
	(In thousands)	Unfunded			Percentage			December 31,				December 31,
		Commitments*			Ownership			2013				2012
	Investment in LPs/LLCs:
	Tax credit partnerships	$	22,441		See below			$	142,174			$	87,310
	Secured debt fund	27,000			<	20%		13,233				—
	Long equity fund	None			<	20%		6,574				—
	Long/Short equity funds	None			<	25%		28,385				17,115
	Non-public equity funds	87,603			<	20%		23,870				16,624
								$	214,236			$	121,049
	* Unfunded commitments are included in the carrying value of tax credit partnerships, only.
Investments held in an unrealized loss position	'
	The following tables provide summarized information with respect to investments held in an unrealized loss position at December 31, 2013 and December 31, 2012, including the length of time the investment had been held in a continuous unrealized loss position.
		31-Dec-13
		Total							Less than 12 months							12 months or longer
		Fair			Unrealized				Fair				Unrealized			Fair		Unrealized
	(In thousands)	Value			Loss				Value				Loss			Value		Loss
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	47,668		$	(1,519	)		$	44,304			$	(1,182	)	$	3,364	$	(337	)
	U.S. Government-sponsored enterprise obligations	6,640			(425		)		5,752				(321		)	888		(104		)
	State and municipal bonds	203,970			(7,927		)		184,401				(6,640		)	19,569		(1,287		)
	Corporate debt	349,277			(13,744		)		324,510				(12,061		)	24,767		(1,683		)
	Residential mortgage-backed securities	93,608			(2,855		)		84,045				(2,393		)	9,563		(462		)
	Agency commercial mortgage-backed securities	11,658			(136		)		11,082				(116		)	576		(20		)
	Other commercial mortgage-backed securities	11,153			(167		)		10,215				(159		)	938		(8		)
	Other asset-backed securities	25,539			(324		)		21,804				(77		)	3,735		(247		)
		$	749,513		$	(27,097	)		$	686,113			$	(22,949	)	$	63,400	$	(4,148	)
	Other investments
	Investments in LPs/LLCs carried at cost	$	14,752		$	(1,059	)		$	13,166			$	(1,018	)	$	1,586	$	(41	)
		31-Dec-12
		Total							Less than 12 months							12 months or longer
		Fair			Unrealized				Fair				Unrealized			Fair		Unrealized
	(In thousands)	Value			Loss				Value				Loss			Value		Loss
	Fixed maturities, available for sale
	U.S. Treasury obligations	$	4,073		$	(51	)		$	4,073			$	(51	)	$	—	$	—
	State and municipal bonds	11,234			(94		)		9,232				(65		)	2,002		(29		)
	Corporate debt	90,154			(1,543		)		81,878				(1,377		)	8,276		(166		)
	Residential mortgage-backed securities	10,721			(210		)		10,029				(205		)	692		(5		)
	Agency commercial mortgage-backed securities	1,643			(25		)		498				(2		)	1,145		(23		)
	Other commercial mortgage-backed securities	2,100			(5		)		1,103				(1		)	997		(4		)
	Other asset-backed securities	10,746			(601		)		7,707				(20		)	3,039		(581		)
		$	130,671		$	(2,529	)		$	114,520			$	(1,721	)	$	16,151	$	(808	)
	Other investments
	Investments in LPs/LLCs carried at cost	$	9,474		$	(851	)		$	8,697			$	(688	)	$	777	$	(163	)
Net Investment Income	'
	Net investment income by investment category was as follows:
		Year Ended December 31
	(In thousands)	2013			2012			2011
	Fixed maturities	$	122,065		$	133,088		$	140,897
	Equities	9,454			6,947			1,808
	Short-term investments and Other invested assets	2,584			660			2,812
	Business owned life insurance	1,960			2,008			2,017
	Investment fees and expenses	(6,798		)	(6,609		)	(6,578		)
	Net investment income	$	129,265		$	136,094		$	140,956
Net realized investment gains (losses)	'
	The following table provides detailed information regarding net realized investment gains (losses):
		Year Ended December 31
	(In thousands)	2013			2012				2011
	Total other-than-temporary impairment losses:
	State and municipal bonds	$	(71	)	$	—			$	—
	Residential mortgage-backed securities	—			(557		)		(782		)
	Corporate debt	—			(878		)		(505		)
	Other investments	—			(131		)		(3,827		)
	High yield asset-backed securities	—			—				(75		)
	Portion recognized in (reclassified from) Other Comprehensive Income:
	Residential mortgage-backed securities	—			(201		)		(823		)
	Net impairment losses recognized in earnings	(71		)	(1,767		)		(6,012		)
	Gross realized gains, available-for-sale securities	18,130			18,645				14,625
	Gross realized (losses), available-for-sale securities	(7,031		)	(2,076		)		(1,754		)
	Net realized gains (losses), trading securities	20,444			1,485				2,212
	Change in unrealized holding gains (losses), trading securities	35,507			12,673				(3,188		)
	Decrease (increase) in the fair value of liabilities carried at fair value	—			(1,245		)		111
	Other	925			1,148				—
	Net realized investment gains (losses)	$	67,904		$	28,863			$	5,994
Cumulative credit losses recorded in earnings related to impaired debt securities for which a portion of the OTTI has been recorded in OCI	'
	The following table presents a roll forward of cumulative credit losses recorded in earnings related to impaired debt securities for which a portion of the other-than-temporary impairment was recorded in Other Comprehensive Income.
	(In thousands)	2013			2012			2011
	Balance January 1	$	3,301		$	5,870		$	4,446
	Additional credit losses recognized during the period, related to securities for which:
	OTTI has been previously recognized	—			268			1,424
	Reductions due to:
	Securities sold during the period (realized)	(3,218		)	(2,837		)	—
	Balance December 31	$	83		$	3,301		$	5,870
Information regarding sales and purchases of available-for-sale securities	'
	Other information regarding sales and purchases of available-for-sale securities is as follows:
		Year Ended December 31
	(In millions)	2013			2012			2011
	Proceeds from sales (exclusive of maturities and paydowns)	$	593.3		$	500.2		$	424.8
	Purchases	$	519.2		$	646.2		$	782.6

Reinsurance_Tables

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Summary of the effect of reinsurance on premiums written and earned	'
	The effect of reinsurance on premiums written and earned was as follows (in thousands):
		2013 Premiums						2012 Premiums						2011 Premiums
		Written			Earned			Written			Earned			Written			Earned
	Direct	$	566,745		$	568,629		$	536,318		$	558,200		$	565,746		$	570,891
	Assumed	802			804			113			116			149			154
	Ceded	(42,365		)	(41,514		)	(8,133		)	(7,652		)	(7,388		)	(5,630		)
	Net premiums	$	525,182		$	527,919		$	528,298		$	550,664		$	558,507		$	565,415

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Components of deferred tax assets and liabilities	'
	Significant components of ProAssurance’s deferred tax assets and liabilities were as follows:
	(In thousands)	2013			2012
	Deferred tax assets
	Unpaid loss discount	$	51,879		$	57,811
	Unearned premium adjustment	21,861			20,497
	Compensation related	18,172			14,634
	Intangibles	2,074			2,214
	Total deferred tax assets	93,986			95,156
	Deferred tax liabilities
	Deferred acquisition costs	10,150			8,112
	Unrealized gains on investments, net	32,127			78,284
	Fixed assets	4,166			5,630
	Basis differentials–investments	31,247			3,029
	Intangibles	13,238			14,311
	Other	1,301			375
	Total deferred tax liabilities	92,229			109,741
	Net deferred tax assets (liabilities)	$	1,757		$	(14,585	)
Reconciliation of unrecognized tax benefits	'
	A reconciliation of the beginning and ending amounts of unrecognized tax benefits for 2013 and 2012 was as follows:
	(In thousands)	2013			2012			2011
	Balance at January 1	$	4,823		$	18,585		$	8,344
	(Decreases) for tax positions taken during the current year	—			(10,206		)	—
	Increases for tax positions taken during prior years	—			—			18,585
	(Decreases) for tax positions taken during prior years	—			(3,556		)	—
	(Decreases) relating to settlements with taxing authorities	—			—			(8,344		)
	Balance at December 31	$	4,823		$	4,823		$	18,585
Reconciliation of expected income tax expense to actual income tax expense	'
	A reconciliation of “expected” income tax expense (35% of income before income taxes) to actual income tax expense in the accompanying financial statements follows:
	(In thousands)	2013			2012			2011
	Computed “expected” tax expense	$	139,005		$	138,588		$	145,109
	Tax-exempt income	(14,509		)	(14,374		)	(13,793		)
	Tax credits	(17,888		)	(10,005		)	(5,654		)
	Non-taxable gain on acquisition	(11,310		)	—			—
	Other	4,338			6,287			1,840
	Total	$	99,636		$	120,496		$	127,502

Reserve_for_Losses_and_Loss_Ad1

Reserve for Losses and Loss Adjustment Expenses (Tables)	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Summary of reserve for losses and loss adjustment expenses	'
	Activity in the reserve for losses and loss adjustment expenses is summarized as follows:
	(In thousands)	2013			2012			2011
	Balance, beginning of year	$	2,054,994		$	2,247,772		$	2,414,100
	Less reinsurance recoverables on unpaid losses and loss adjustment expenses	191,645			247,658			277,436
	Net balance, beginning of year	1,863,349			2,000,114			2,136,664
	Net reserves acquired from acquisitions	126,007			22,464			—
	Net losses:
	Current year	447,510			451,951			488,152
	Favorable development of reserves established in prior years, net	(222,749		)	(272,038		)	(325,865		)
	Total	224,761			179,913			162,287
	Paid related to:
	Current year	(43,616		)	(38,439		)	(34,240		)
	Prior years	(345,197		)	(300,703		)	(264,597		)
	Total paid	(388,813		)	(339,142		)	(298,837		)
	Net balance, end of year	1,825,304			1,863,349			2,000,114
	Plus reinsurance recoverables on unpaid losses and loss adjustment expenses	247,518			191,645			247,658
	Balance, end of year	$	2,072,822		$	2,054,994		$	2,247,772

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of future minimum lease payments for operating leases	'
	The following is a schedule of future minimum lease payments for operating leases that had initial or remaining non-cancelable lease terms in excess of one year as of December 31, 2013.
	Operating Leases
	(In thousands)
	2014	$	3,039
	2015	2,750
	2016	2,553
	2017	2,394
	Thereafter	9,175
	Total minimum lease payments	$	19,911

Longterm_Debt_Tables

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Outstanding long-term debt	'
	ProAssurance’s outstanding long-term debt consisted of the following:
	(In thousands)	December 31,		December 31,
		2013		2012
	Senior notes due 2023, unsecured, interest at 5.3% annually	$	250,000	$	—
	Revolving credit agreement, expires in 2016	—		125,000
		$	250,000	$	125,000

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Reclassification adjustments related to available-for-sale securities	'
	Amounts reclassified from accumulated other comprehensive income to net income during the years ended December 31, 2013, 2012 and 2011 all related to available-for-sale securities and included the following:
	(In thousands)	2013			2012			2011
	Reclassifications from accumulated other comprehensive income to net income, available for sale securities:
	Realized investment gains (losses)	$	11,375		$	17,350		$	13,101
	Non-credit impairment losses reclassified to earnings, due to sale of securities or reclassification as a credit loss	(347		)	(2,417		)	(2,415		)
	Total amounts reclassified, before tax effect	11,028			14,933			10,686
	Tax effect (at 35%)	(3,860		)	(5,227		)	(3,740		)
	Net reclassification adjustments	$	7,168		$	9,706		$	6,946

ShareBased_Payments_Tables

Share-Based Payments (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of compensation expense and related tax benefit recognized during each period, and compensation cost expense in future periods	'
	The following table provides a summary of compensation expense and compensation cost that will be charged to expense in future periods, by award type, and the total related tax benefit recognized during each period.
		Share-Based										Unrecognized Compensation Cost
		Compensation Expense
		Year Ended December 31										31-Dec-13
		2013			2012			2011				Amount				Remaining
																Recognition Period
		(In millions)										(In millions)				(Weighted average years)
	Stock Options	$	—		$	—		$	0.1			$	—			N/A
	Restricted Share Units	1.6			1.6			1.3				2.1				1.7
	Performance Share Units	7.1			6.7			5.6				8.1				1.7
	Purchase Match Units	0.5			0.3			0.1				1.5				2.2
	Total share-based compensation expense	$	9.2		$	8.6		$	7.1			$	11.7
	Tax benefit recognized	$	3.2		$	3		$	2.5
Summary of activity for stock options	'
	Activity for stock options during 2013, 2012 and 2011 is summarized below.
		2013					2012							2011
		Options		Weighted			Options			Weighted				Options			Weighted
				Average						Average							Average
				Exercise						Exercise							Exercise
				Price						Price							Price
	Outstanding, beginning of year	20,302		$	23.15		1,014,661			$	22.76			1,430,105			$	21.85
	Granted	—		—			—			—				—			—
	Exercised	(2,220	)	24.28			(994,148	)		22.75				(412,695	)		19.61
	Forfeited or expired	—		—			(211	)		25.67				(2,749	)		25.36
	Outstanding at end of year	18,082		23			20,302			23.15				1,014,661			22.76
	Exercisable at end of year	18,082		23			20,302			23.15				959,889			22.59
	Outstanding at end of year,	18,082		23			20,302			23.15				1,014,064			22.75
	vested or expected to vest
Summary of activity related to management share awards	'
	Activity for restricted share units during 2013, 2012 and 2011 is summarized below. Grant date fair values are based on the market value of a ProAssurance common share on the date of grant.
		2013					2012							2011
		Units		Weighted			Units			Weighted				Units			Weighted
				Average						Average							Average
				Grant Date						Grant Date							Grant Date
				Fair Value						Fair Value							Fair Value
	Beginning non-vested balance	157,212		$	31.94		167,236			$	25.52			120,478			$	23.88
	Granted	39,400		46.97			51,864			42.22				52,256			29.27
	Forfeited	(603	)	35.91			(2,823	)		35.23				(5,075	)		25.38
	Vested and released	(57,239	)	25.25			(59,065	)		22.61				(423	)		22.56
	Ending non-vested balance	138,770		38.92			157,212			31.94				167,236			25.52
Summarized activity for performance share awards	'
	The table reflects the base number of units; actual awards that vest depends upon the extent to which performance objectives are achieved. Grant date fair values are based on the market value of a ProAssurance common share on the date of grant.
		2013					2012							2011
		Base Units		Weighted			Base Units			Weighted				Base Units			Weighted
				Average						Average							Average
				Grant Date						Grant Date							Grant Date
				Fair Value						Fair Value							Fair Value
	Beginning non-vested balance	552,417		$	33.21		522,599			$	26.36			493,661			$	24.56
	Granted	145,580		46.97			212,205			42.22				196,186			30.3
	Forfeited	(17,043	)	38.9			(20,492	)		31.44				(15,804	)		26.28
	Vested and released	(194,274	)	26.39			(161,895	)		23.13				(151,444	)		25.61
	Ending non-vested balance	486,680		39.86			552,417			33.21				522,599			26.36
	Common shares issued due to vesting of awards	135,044					114,884							112,822
Market value of ProAssurance common share on the grant date fair value	'
	Purchase match unit activity during 2013, 2012 and 2011 is summarized below. Grant date fair values are based on the market value of a ProAssurance common share on the date of grant.
		2013					2012							2011
		Units		Weighted			Units			Weighted				Units			Weighted
				Average						Average							Average
				Grant  Date						Grant  Date							Grant  Date
				Fair Value						Fair Value							Fair Value
	Beginning non-vested balance	40,985		$	39.85		18,900			$	36.2			—			$	—
	Granted	25,151		43.57			23,799			42.59				19,016			36.2
	Forfeited	(2,456	)	40.71			(1,610	)		37.72				(116	)		36.2
	Vested and released	(555	)	36.33			(104	)		36.2				—			—
	Ending non-vested balance	63,125		41.34			40,985			39.85				18,900			36.2

Statutory_Accounting_and_Divid1

Statutory Accounting and Dividend Restrictions (Tables)	12 Months Ended
	Dec. 31, 2013
Statutory Accounting And Dividend Restrictions [Abstract]	'
Consolidated net income	'
	Net earnings and capital and surplus of ProAssurance’s insurance subsidiaries on a statutory basis are shown in the following table. The table does not include Eastern, as the acquisition occurred on January 1, 2014 (see Note 18).
	(In millions)
	Statutory Net Earnings			Statutory Capital and Surplus
	2013	2012	2011	2013	2012
	$256	$312	$291	$1,642	$1,499

Quarterly_Results_of_Operation1

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Data [Abstract]	'
Summary of unaudited quarterly results of operations	'
	The following is a summary of unaudited quarterly results of operations for 2013 and 2012:
			2013
	(In thousands, except per share data)		1st			2nd			3rd			4th
	Net premiums earned		$	134,578		$	130,352		$	133,598		$	129,392
	Net losses and loss adjustment expenses:
	Current year		110,726			109,109			110,987			116,689
	Prior year		(53,100		)	(38,500		)	(49,350		)	(81,799		)
	Net income		112,850			50,451			63,357			70,864
	Basic earnings per share*		1.83			0.82			1.02			1.15
	Diluted earnings per share*		1.82			0.81			1.02			1.14
			2012
	(In thousands, except per share data)		1st			2nd			3rd			4th
	Net premiums earned		$	136,659		$	131,266		$	127,125		$	155,615
	Net losses and loss adjustment expenses:
	Current year		117,656			108,134			106,621			119,539
	Prior year		(47,457		)	(60,050		)	(50,000		)	(114,531		)
	Net income		55,645			58,453			60,106			101,266
	Basic earnings per share*		0.91			0.95			0.98			1.65
	Diluted earnings per share*		0.9			0.95			0.97			1.64
	*	Quarterly and year-to-date computations of per share amounts are made independently; therefore, the sum of per share amounts for the quarters may not equal per share amounts for the respective year-to-date periods.

Schedule_II_Condensed_Financia1

Schedule II - Condensed Financial Information of Registrant Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Schedule Of Debt Instruments of Parent Company Only Disclosure [Table Text Block]	'
	Outstanding long-term debt, as of December 31, 2013 and 2012, consists of the following:
	(In thousands)	2013		2012
	Senior notes due 2023, unsecured, interest at 5.3% annually	$	250,000	$	—
	Revolving credit agreement, expires in 2016	—		125,000
		$	250,000	$	125,000

Accounting_Policies_Details

Accounting Policies (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Premium Receivables [Member]	'	'
Summary of allowances for credit losses related to premium and agency receivables	'	'
Allowance for credit losses, Beginning balance	$1,000	$990
Estimated credit losses	236	157
Account write offs, net of recoveries	-246	-147
Allowance for credit losses, Ending balance	990	1,000
Agency Receivables [Member]	'	'
Summary of allowances for credit losses related to premium and agency receivables	'	'
Allowance for credit losses, Beginning balance	286	332
Estimated credit losses	0	0
Account write offs, net of recoveries	-236	-46
Allowance for credit losses, Ending balance	$50	$286

Accounting_Policies_Details_Te

Accounting Policies (Details Textual) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 27, 2012	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
				Segment
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'
Stock split, conversion ratio	2	'	'	'	'	'
Gain on acquisition	'	($3,700,000)	$36,000,000	$32,314,000	$0	$0
Insurance policy duration	'	'	'	'1 year	'	'
Percentage of tax benefit	'	'	'	50.00%	'	'
Real estate depreciation expense	'	'	'	4,538,000	4,741,000	4,949,000
Carrying value of finite-lived intangible assets	'	51,700,000	'	51,700,000	50,200,000	'
Carrying value of indefinite lived intangible assets	'	16,800,000	'	16,800,000	14,300,000	'
Accumulated amortization of intangible assets	'	16,500,000	'	16,500,000	11,200,000	'
Amortization expense for intangible assets	'	'	'	5,300,000	4,500,000	4,700,000
Estimated aggregate amortization of intangible assets for 2013	'	5,100,000	'	5,100,000	'	'
Estimated aggregate amortization of intangible assets for 2014	'	3,100,000	'	3,100,000	'	'
Estimated aggregate amortization of intangible assets for 2015	'	2,800,000	'	2,800,000	'	'
Estimated aggregate amortization of intangible assets for 2016	'	2,800,000	'	2,800,000	'	'
Estimated aggregate amortization of intangible assets for 2017	'	2,400,000	'	2,400,000	'	'
Number of reportable segments	'	'	'	1	'	'
Goodwill impairment loss	'	'	'	0	'	'
Goodwill purchase accounting adjustments decrease	'	'	'	1,900,000	'	'
Building and Building Improvements [Member]	'	'	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'
Real estate accumulated depreciation	'	21,600,000	'	21,600,000	20,200,000	'
Real estate depreciation expense	'	'	'	1,500,000	1,400,000	1,700,000
Eastern Insurance Holdings [Member]	'	'	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'
Third party conversion agent asset	'	$205,000,000	'	$205,000,000	'	'

Business_Combinations_Details

Business Combinations (Details) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Sep. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jan. 02, 2013

Dec. 31, 2013

Dec. 31, 2013

Medmarc [Member]

Medmarc [Member]

Medmarc [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fixed maturities, available for sale

'

'

'

'

'

'

'

'

'

'

'

'

$269,529

'

'

Equity securities, trading

'

'

'

'

'

'

'

'

'

'

'

'

30,976

'

'

Cash and short-term investments

'

'

'

'

'

'

'

'

'

'

'

'

24,008

'

'

Other investments

'

'

'

'

'

'

'

'

'

'

'

'

5,340

'

'

Premiums receivable

'

'

'

'

'

'

'

'

'

'

'

'

2,986

'

'

Receivable from reinsurers on paid and unpaid losses and LAE

'

'

'

'

'

'

'

'

'

'

'

'

73,107

'

'

Intangible assets

'

'

'

'

'

'

'

'

'

'

'

'

3,630

'

'

Other assets

'

'

'

'

'

'

'

'

'

'

'

'

14,614

'

'

Reserve for losses and loss adjustment expenses

'

'

'

'

'

'

'

'

'

'

'

'

-201,072

'

'

Unearned premiums

'

'

'

'

'

'

'

'

'

'

'

'

-16,937

'

'

Deferred tax liabilities

'

'

'

'

'

'

'

'

'

'

'

'

-4,934

'

'

Other liabilities

'

'

'

'

'

'

'

'

'

'

'

'

-15,233

'

'

Fair value of net assets acquired

'

'

'

'

'

'

'

'

'

'

'

'

186,014

'

'

Gain on acquisition

3,700

'

'

'

'

'

'

'

-36,000

-32,314

0

0

-32,314

3,700

-32,300

Total purchase consideration

'

'

'

'

'

'

'

'

'

'

'

'

153,700

'

'

ProAssurance Consolidated results

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proforma Consolidated Results, Revenue

'

'

'

'

'

'

'

'

'

740,178

757,240

'

'

'

'

Proforma Consolidated Results, Earnings

'

'

'

'

'

'

'

'

'

263,820

317,097

'

'

'

'

Actual Consolidated Results, Revenue

'

'

'

'

'

'

'

'

'

740,178

715,854

716,784

'

'

'

Actual Consolidated Results, Net Income

$70,864

$63,357

$50,451

$112,850

$101,266

$60,106

$58,453

$55,645

'

$297,523

$275,470

$287,096

'

'

'

Business_Combinations_Details_

Business Combinations (Details Textual) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jan. 02, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Jan. 02, 2013

Jan. 02, 2014

Jan. 02, 2013

Business

Medmarc [Member]

Medmarc [Member]

Medmarc [Member]

Medmarc [Member]

Eastern Insurance Holdings [Member]

Noncompete Agreements [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Medmarc [Member]

Eastern Insurance Holdings [Member]

Eastern Insurance Holdings [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of acquisitions acquired

'

'

'

'

0

'

'

'

'

'

'

'

'

Total purchase consideration

'

'

'

'

'

$153,700,000

'

'

'

'

'

$205,000,000

'

Business acquisition, related premium credits to eligible policyholders

'

'

'

'

'

7,500,000

'

'

'

'

'

'

'

Expenses related to the purchase of business

'

'

'

'

'

'

'

2,600,000

1,000,000

'

'

'

'

Gain on acquisition

-3,700,000

36,000,000

32,314,000

0

0

32,314,000

-3,700,000

32,300,000

'

'

'

'

'

Intangible asset, useful life

'

'

'

'

'

'

'

'

'

'

'2 years

'

'

Profit margin used in fair value estimate of acquired reserves for losses and related reinsurance recoverables

'

'

'

'

'

5.00%

'

'

'

'

'

'

'

Risk premium used in fair value estimate of acquired reserves for losses and related reinsurance recoverables

'

'

'

'

'

5.00%

'

'

'

'

'

'

'

Revenue of aquiree since acquisition date

'

'

'

'

'

'

'

46,500,000

'

'

'

'

'

Earnings of acquiree since acquisition date

'

'

'

'

'

'

'

15,700,000

'

'

'

'

'

Third party conversion agent asset

'

'

'

'

'

'

'

'

$153,700,000

$205,000,000

'

'

'

Voting interests acquired

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

Fair_Value_Measurement_Details

Fair Value Measurement (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Assets:	'	'
Equity securities, trading, at fair value	$253,541	$202,618
Level 3 [Member] | State and municipal bonds [Member]	'	'
Financial instruments carried at fair value, classified as a part of:	'	'
Total assets	7,300	7,200
Level 3 [Member] | Other asset-backed securities [Member]	'	'
Financial instruments carried at fair value, classified as a part of:	'	'
Total assets	6,800	4,000
Fair Value, Measurements, Recurring [Member]	'	'
Financial instruments carried at fair value, classified as a part of:	'	'
Investment in unconsolidated subsidiaries	72,062	33,739
Total assets	3,692,257	3,756,093
Fair Value, Measurements, Recurring [Member] | U.S. Treasury obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	170,714	205,857
Fair Value, Measurements, Recurring [Member] | U.S. Government-sponsored enterprise obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	32,768	56,947
Fair Value, Measurements, Recurring [Member] | State and municipal bonds [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	1,154,666	1,219,979
Fair Value, Measurements, Recurring [Member] | Corporate debt, multiple observable inputs [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	1,346,977	1,455,333
Fair Value, Measurements, Recurring [Member] | Private placement senior notes [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	'	346
Fair Value, Measurements, Recurring [Member] | Other corporate debt, NRSRO ratings available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	11,449	13,835
Fair Value, Measurements, Recurring [Member] | Other corporate debt, NRSRO ratings not available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	2,727	1,010
Fair Value, Measurements, Recurring [Member] | Residential mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	235,614	289,850
Fair Value, Measurements, Recurring [Member] | Agency commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	27,475	59,464
Fair Value, Measurements, Recurring [Member] | Other commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	61,390	74,106
Fair Value, Measurements, Recurring [Member] | Other asset-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	74,269	71,272
Fair Value, Measurements, Recurring [Member] | Financial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	81,536	70,900
Fair Value, Measurements, Recurring [Member] | Utilities/Energy [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	32,350	31,383
Fair Value, Measurements, Recurring [Member] | Consumer oriented [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	66,461	51,100
Fair Value, Measurements, Recurring [Member] | Industrial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	57,262	29,695
Fair Value, Measurements, Recurring [Member] | All other [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	15,932	19,540
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member]	'	'
Assets:	'	'
Short-term investments	248,605	71,737
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]	'	'
Financial instruments carried at fair value, classified as a part of:	'	'
Investment in unconsolidated subsidiaries	0	0
Total assets	502,146	262,379
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Treasury obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Government-sponsored enterprise obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | State and municipal bonds [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate debt, multiple observable inputs [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Private placement senior notes [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	'	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other corporate debt, NRSRO ratings available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other corporate debt, NRSRO ratings not available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Residential mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other asset-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	81,536	70,900
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Utilities/Energy [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	32,350	31,383
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Consumer oriented [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	66,461	51,100
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Industrial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	57,262	29,695
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | All other [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	15,932	19,540
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Short-term Investments [Member]	'	'
Assets:	'	'
Short-term investments	248,605	59,761
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]	'	'
Financial instruments carried at fair value, classified as a part of:	'	'
Investment in unconsolidated subsidiaries	0	0
Total assets	3,089,721	3,433,574
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Treasury obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	170,714	205,857
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Government-sponsored enterprise obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	32,768	56,947
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | State and municipal bonds [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	1,147,328	1,212,804
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate debt, multiple observable inputs [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	1,346,977	1,455,333
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Private placement senior notes [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	'	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other corporate debt, NRSRO ratings available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other corporate debt, NRSRO ratings not available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Residential mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	235,614	289,850
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	27,475	59,464
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	61,390	74,106
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other asset-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	67,455	67,237
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Utilities/Energy [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Consumer oriented [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Industrial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | All other [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Short-term Investments [Member]	'	'
Assets:	'	'
Short-term investments	0	11,976
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]	'	'
Financial instruments carried at fair value, classified as a part of:	'	'
Investment in unconsolidated subsidiaries	72,062	33,739
Total assets	100,390	60,140
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | U.S. Treasury obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | U.S. Government-sponsored enterprise obligations [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | State and municipal bonds [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	7,338	7,175
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate debt, multiple observable inputs [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Private placement senior notes [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	'	346
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Other corporate debt, NRSRO ratings available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	11,449	13,835
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Other corporate debt, NRSRO ratings not available [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	2,727	1,010
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Residential mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Other commercial mortgage-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Other asset-backed securities [Member]	'	'
Assets:	'	'
Fair value of available for sale securities	6,814	4,035
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Utilities/Energy [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Consumer oriented [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Industrial [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | All other [Member]	'	'
Assets:	'	'
Equity securities, trading, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Short-term Investments [Member]	'	'
Assets:	'	'
Short-term investments	$0	$0

Fair_Value_Measurement_Details1

Fair Value Measurement (Details 1) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Secured debt fund [Member]	'		'
Investments in private funds [Abstract]	'		'
Investments in limited liability companies and limited partnerships unfunded commitments	$27,000	[1]	'
Investments in limited liability companies and limited partnerships fair value	13,233	[1]	0	[1]
Private equity fund [Member]	'		'
Investments in private funds [Abstract]	'		'
Investments in limited liability companies and limited partnerships unfunded commitments	0	[2]	'
Investments in limited liability companies and limited partnerships fair value	6,574	[2]	0	[2]
Long/Short equity funds [Member]	'		'
Investments in private funds [Abstract]	'		'
Investments in limited liability companies and limited partnerships unfunded commitments	0	[3]	'
Investments in limited liability companies and limited partnerships fair value	28,385	[3]	17,115	[3]
Non-public equity funds [Member]	'		'
Investments in private funds [Abstract]	'		'
Investments in limited liability companies and limited partnerships unfunded commitments	87,603	[4]	'
Investments in limited liability companies and limited partnerships fair value	23,870	[4]	16,624	[4]
Investment in unconsolidated subsidiaries [Member]	'		'
Investments in private funds [Abstract]	'		'
Investments in limited liability companies and limited partnerships fair value	$72,062		$33,739
[1]	The LP is structured to provide income and capital appreciation primarily through investments in senior secured debt. Redemptions are not allowed. Income and capital are to be periodically distributed at the discretion of the LP over an anticipated time frame that spans from 7 to 9 years.
[2]	The LP holds long equities of public international companies. Redemptions are allowed at the end of any calendar month with a prior notice requirement of 15 days and are paid within 10 days of the end of the calendar month of the redemption request.
[3]	Comprised of interests in two unrelated LP funds, each holds primarily long and short U.S. and North American equities, and targets absolute returns using a strategy designed to take advantage of event-driven market opportunities. One LP allows redemption with a notice requirement of up to 45 days with the redemption payable within 30 days of the redemption date, unless the redemption request is for 90% or more of the requestor’s capital balance. Redemptions at the 90% and above level will be paid at 90%, with the remainder paid after the LP’s annual audit. The other LP generally allows redemption of substantially all the capital semi-annually with 30 days notice.
[4]	Comprised of interests in three unrelated LP funds, each structured to provide capital appreciation through diversified investments in private equity, which can include investments in buyout, venture capital, mezzanine debt, distressed debt and other private equity-oriented LPs. One LP allows redemption by special consent; the others do not permit redemption. Income and capital are to be periodically distributed at the discretion of the LP over time frames that are anticipated to span from 4 to 12 years.

Fair_Value_Measurement_Details2

Fair Value Measurement (Details 2) (Fair Value, Inputs, Level 3 [Member], USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

In Thousands, unless otherwise specified

State and municipal bonds [Member]

State and municipal bonds [Member]

State and municipal bonds [Member]

State and municipal bonds [Member]

State and municipal bonds [Member]

State and municipal bonds [Member]

State and municipal bonds [Member]

State and municipal bonds [Member]

Corporate debt with limited observable inputs [Member]

Corporate debt with limited observable inputs [Member]

Corporate debt with limited observable inputs [Member]

Corporate debt with limited observable inputs [Member]

Corporate debt with limited observable inputs [Member]

Corporate debt with limited observable inputs [Member]

Corporate debt with limited observable inputs [Member]

Corporate debt with limited observable inputs [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Asset-backed Securities, Securitized Loans and Receivables [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Income Approach Valuation Technique [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total assets

$7,300

$7,200

'

'

'

'

'

'

$14,200

$15,200

'

'

'

'

'

'

$6,800

$4,000

'

'

'

'

'

'

Comparability Adjustment

'

'

10.00%

0.00%

5.00%

10.00%

0.00%

5.00%

'

'

5.00%

0.00%

2.50%

5.00%

0.00%

2.50%

'

'

5.00%

0.00%

2.50%

5.00%

0.00%

2.50%

Fair_Value_Measurement_Details3

Fair Value Measurement (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'	'
Beginning Balance	$60,140	$54,996
Included in earnings, as a part of:	'	'
Included in other comprehensive income	-785	646
Purchases	35,393	20,878
Sales	-18,385	-4,482
Transfers in	29,737	9,220
Transfers out	-12,354	-21,289
Ending Balance	100,390	60,140
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	6,877	147
State and municipal bonds [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'	'
Beginning Balance	7,175	7,200
Included in earnings, as a part of:	'	'
Included in other comprehensive income	1	0
Purchases	0	0
Sales	-2,106	-25
Transfers in	2,312	0
Transfers out	0	0
Ending Balance	7,338	7,175
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	0	0
Corporate debt [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'	'
Beginning Balance	15,191	8,082
Included in earnings, as a part of:	'	'
Included in other comprehensive income	-725	611
Purchases	9,470	3,136
Sales	-1,629	-1,951
Transfers in	2,114	9,220
Transfers out	-10,073	-3,931
Ending Balance	14,176	15,191
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	0	0
Asset-backed securities [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'	'
Beginning Balance	4,035	0
Included in earnings, as a part of:	'	'
Included in other comprehensive income	-61	35
Purchases	1,356	6,734
Sales	-18	-1,118
Transfers in	3,800	0
Transfers out	-2,281	-1,616
Ending Balance	6,814	4,035
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	0	0
Investment in unconsolidated subsidiaries [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'	'
Beginning Balance	33,739	23,841
Included in earnings, as a part of:	'	'
Included in other comprehensive income	0	0
Purchases	24,567	11,008
Sales	-14,632	-1,388
Transfers in	21,511	0
Transfers out	0	0
Ending Balance	72,062	33,739
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	6,877	278
Other Investments [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'	'
Beginning Balance	0	15,873
Included in earnings, as a part of:	'	'
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Transfers in	0	0
Transfers out	0	-15,742
Ending Balance	0	0
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	0	-131
Net investment income [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	-120	14
Net investment income [Member] | State and municipal bonds [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Net investment income [Member] | Corporate debt [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	-103	14
Net investment income [Member] | Asset-backed securities [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	-17	0
Net investment income [Member] | Investment in unconsolidated subsidiaries [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Net investment income [Member] | Other Investments [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Equity in earnings of unconsolidated subsidiaries [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	6,877	278
Equity in earnings of unconsolidated subsidiaries [Member] | State and municipal bonds [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Equity in earnings of unconsolidated subsidiaries [Member] | Corporate debt [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Equity in earnings of unconsolidated subsidiaries [Member] | Asset-backed securities [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Equity in earnings of unconsolidated subsidiaries [Member] | Investment in unconsolidated subsidiaries [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	6,877	278
Equity in earnings of unconsolidated subsidiaries [Member] | Other Investments [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Net realized investment gains (losses) [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	-113	-121
Net realized investment gains (losses) [Member] | State and municipal bonds [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	-44	0
Net realized investment gains (losses) [Member] | Corporate debt [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	-69	10
Net realized investment gains (losses) [Member] | Asset-backed securities [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Net realized investment gains (losses) [Member] | Investment in unconsolidated subsidiaries [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	0	0
Net realized investment gains (losses) [Member] | Other Investments [Member]	'	'
Included in earnings, as a part of:	'	'
Net investment income	$0	($131)

Fair_Value_Measurement_Details4

Fair Value Measurement (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'
Beginning Balance	$18,839
Included in earnings as a part of:	'
Settlements	-22,247
Ending Balance	0
Change in unrealized (gains) losses included in earnings for the above period for Level 3 liabilities outstanding at period-end	0
2019 Note Payable [Member]	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'
Beginning Balance	14,180
Included in earnings as a part of:	'
Settlements	-17,112
Ending Balance	0
Change in unrealized (gains) losses included in earnings for the above period for Level 3 liabilities outstanding at period-end	0
Interest rate swap agreement [Member]	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:	'
Beginning Balance	4,659
Included in earnings as a part of:	'
Settlements	-5,135
Ending Balance	0
Change in unrealized (gains) losses included in earnings for the above period for Level 3 liabilities outstanding at period-end	0
Net realized investment gains (losses) [Member]	'
Included in earnings as a part of:	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	1,245
Net realized investment gains (losses) [Member] | 2019 Note Payable [Member]	'
Included in earnings as a part of:	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	769
Net realized investment gains (losses) [Member] | Interest rate swap agreement [Member]	'
Included in earnings as a part of:	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	476
Loss on extinguishment of debt [Member]	'
Included in earnings as a part of:	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	2,163
Loss on extinguishment of debt [Member] | 2019 Note Payable [Member]	'
Included in earnings as a part of:	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	2,163
Loss on extinguishment of debt [Member] | Interest rate swap agreement [Member]	'
Included in earnings as a part of:	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	$0

Fair_Value_Measurement_Details5

Fair Value Measurement (Details 5) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Financial assets:	'	'
BOLI	$54,374	$52,414
Investment in unconsolidated subsidiaries	214,236	121,049
Other investments	52,240	31,085
Other assets	329,979	234,286
Financial liabilities:	'	'
Notes payable, fair value disclosure	250,000	125,000
Other liabilities	143,079	131,967
Not Measured At Fair Value [Member] | Carrying Value [Member]	'	'
Financial assets:	'	'
BOLI	54,374	31,085
Investment in unconsolidated subsidiaries	142,174	87,310
Other investments	52,240	52,414
Other assets	17,940	11,400
Financial liabilities:	'	'
Other liabilities	13,303	12,130
Not Measured At Fair Value [Member] | Carrying Value [Member] | Senior notes due 2023 [Member]	'	'
Financial liabilities:	'	'
Notes payable, fair value disclosure	250,000	0
Not Measured At Fair Value [Member] | Carrying Value [Member] | Revolving credit agreement [Member]	'	'
Financial liabilities:	'	'
Notes payable, fair value disclosure	0	125,000
Not Measured At Fair Value [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value [Member]	'	'
Financial assets:	'	'
BOLI	54,374	38,656
Investment in unconsolidated subsidiaries	139,548	91,528
Other investments	51,833	52,414
Other assets	17,940	11,385
Financial liabilities:	'	'
Other liabilities	13,303	12,085
Not Measured At Fair Value [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value [Member] | Senior notes due 2023 [Member]	'	'
Financial liabilities:	'	'
Notes payable, fair value disclosure	262,500	0
Not Measured At Fair Value [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value [Member] | Revolving credit agreement [Member]	'	'
Financial liabilities:	'	'
Notes payable, fair value disclosure	$0	$125,000

Fair_Value_Measurement_Details6

Fair Value Measurement (Details Textuals) (Details)	12 Months Ended
	Dec. 31, 2013
Private equity fund [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Notice period required for redemption of LP valued at NAV	'15 days
Long/Short equity funds [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Redemption Percentage of LP at NAV for which initial payment is limited	90.00%
Payment percentage for redemption of LP at NAV for which initial payment is limited	90.00%
Minimum [Member] | Secured debt fund [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Anticipated time frame for distribution at the discretion of the LP	'7 years
Minimum [Member] | Non-public equity funds [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Anticipated time frame for distribution at the discretion of the LP	'4 years
Maximum [Member] | Secured debt fund [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Anticipated time frame for distribution at the discretion of the LP	'9 years
Maximum [Member] | Private equity fund [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Payment period for redemption of LP valued at NAV	'10 days
Maximum [Member] | Long/Short equity funds [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Notice period required for redemption of LP valued at NAV	'45 days
Payment period for redemption of LP valued at NAV	'30 days
Maximum [Member] | Non-public equity funds [Member]	'
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]	'
Anticipated time frame for distribution at the discretion of the LP	'12 years

Fair_Value_Measurement_Details7

Fair Value Measurement (Details Textuals 1) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Transfers between Level 1 to Level 2	$0	$0
Transfers between Level 2 to Level 1	'	0
Short-term Investments [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Transfers between Level 2 to Level 1	$7,200,000	'

Investments_Details

Investments (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
U.S. Treasury obligations [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	$166,115	$191,642
Gross Unrealized Gains	6,118	14,266
Gross Unrealized Losses	-1,519	-51
Total Fair Value	170,714	205,857
U.S. Government-sponsored enterprise obligations [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	30,942	52,110
Gross Unrealized Gains	2,251	4,837
Gross Unrealized Losses	-425	0
Total Fair Value	32,768	56,947
State and municipal bonds [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	1,116,060	1,134,744
Gross Unrealized Gains	46,533	85,329
Gross Unrealized Losses	-7,927	-94
Total Fair Value	1,154,666	1,219,979
Corporate debt [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	1,321,838	1,375,880
Gross Unrealized Gains	53,059	96,187
Gross Unrealized Losses	-13,744	-1,543
Total Fair Value	1,361,153	1,470,524
Residential mortgage-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	230,861	272,990
Gross Unrealized Gains	7,608	17,070
Gross Unrealized Losses	-2,855	-210
Total Fair Value	235,614	289,850
Agency commercial mortgage-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	27,268	57,234
Gross Unrealized Gains	343	2,255
Gross Unrealized Losses	-136	-25
Total Fair Value	27,475	59,464
Other commercial mortgage-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	59,066	69,062
Gross Unrealized Gains	2,491	5,049
Gross Unrealized Losses	-167	-5
Total Fair Value	61,390	74,106
Other asset-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	74,106	70,670
Gross Unrealized Gains	487	1,203
Gross Unrealized Losses	-324	-601
Total Fair Value	74,269	71,272
Debt Securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	3,026,256	3,224,332
Gross Unrealized Gains	118,890	226,196
Gross Unrealized Losses	-27,097	-2,529
Total Fair Value	$3,118,049	$3,447,999

Investments_Details_1

Investments (Details 1) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
U.S. Treasury obligations [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	$166,115	$191,642
Due in one year or less	15,501	'
Due after one year through five years	107,433	'
Due after five years through ten years	44,102	'
Due after ten years	3,678	'
Total Fair Value	170,714	205,857
U.S. Government-sponsored enterprise obligations [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	30,942	52,110
Due in one year or less	3,226	'
Due after one year through five years	21,564	'
Due after five years through ten years	7,759	'
Due after ten years	219	'
Total Fair Value	32,768	56,947
State and municipal bonds [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	1,116,060	1,134,744
Due in one year or less	57,081	'
Due after one year through five years	406,444	'
Due after five years through ten years	467,219	'
Due after ten years	223,922	'
Total Fair Value	1,154,666	1,219,979
Corporate debt [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	1,321,838	1,375,880
Due in one year or less	124,080	'
Due after one year through five years	578,894	'
Due after five years through ten years	627,496	'
Due after ten years	30,683	'
Total Fair Value	1,361,153	1,470,524
Residential mortgage-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	230,861	272,990
Total Fair Value	235,614	289,850
Agency commercial mortgage-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	27,268	57,234
Total Fair Value	27,475	59,464
Other commercial mortgage-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	59,066	69,062
Total Fair Value	61,390	74,106
Other asset-backed securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	74,106	70,670
Total Fair Value	74,269	71,272
Debt Securities [Member]	'	'
Fixed maturities, available for sale	'	'
Amortized Cost	3,026,256	3,224,332
Total Fair Value	$3,118,049	$3,447,999

Investments_Details_2

Investments (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other Investments	'	'
Other investments	$52,240	$31,085
Investments in LPs/LLCs, at cost [Member]	'	'
Other Investments	'	'
Other investments	47,258	25,092
FHLB capital stock, at cost [Member]	'	'
Other Investments	'	'
Other investments	3,449	4,278
Other, principally an annuity, at amortized cost [Member]	'	'
Other Investments	'	'
Other investments	$1,533	$1,715

Investments_Details_3

Investments (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Unconsolidated Subsidiaries	'	'
Carrying Value	$214,236	$121,049
Tax credit partnerships [Member]	'	'
Unconsolidated Subsidiaries	'	'
Unfunded Commitments	22,441	'
Carrying Value	142,174	87,310
Secured debt fund [Member]	'	'
Unconsolidated Subsidiaries	'	'
Unfunded Commitments	27,000	'
Carrying Value	13,233	0
Secured debt fund [Member] | Maximum [Member]	'	'
Unconsolidated Subsidiaries	'	'
Percentage Ownership	20.00%	'
Long equity fund [Member]	'	'
Unconsolidated Subsidiaries	'	'
Unfunded Commitments	0	'
Carrying Value	6,574	0
Long equity fund [Member] | Maximum [Member]	'	'
Unconsolidated Subsidiaries	'	'
Percentage Ownership	20.00%	'
Long/Short equity funds [Member]	'	'
Unconsolidated Subsidiaries	'	'
Unfunded Commitments	0	'
Carrying Value	28,385	17,115
Long/Short equity funds [Member] | Maximum [Member]	'	'
Unconsolidated Subsidiaries	'	'
Percentage Ownership	25.00%	'
Non-public equity funds [Member]	'	'
Unconsolidated Subsidiaries	'	'
Unfunded Commitments	87,603	'
Carrying Value	$23,870	$16,624
Non-public equity funds [Member] | Maximum [Member]	'	'
Unconsolidated Subsidiaries	'	'
Percentage Ownership	20.00%	'

Investments_Details_4

Investments (Details 4) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investments in LPs/LLCs [Member]	'	'
Investments held in an unrealized loss position	'	'
Other Investments, Continuous Unrealized Loss Position, Fair Value	$14,752	$9,474
Other Investments, Continuous Unrealized Loss Position, Aggregate Losses	-1,059	-851
Other investments, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	13,166	8,697
Other Investments, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	-1,018	-688
Other Investments, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,586	777
Other Investments, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	-41	-163
U.S. Treasury obligations [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	47,668	4,073
Unrealized Loss	-1,519	-51
Less than 12 months, Fair Value	44,304	4,073
Less than 12 months, Unrealized Loss	-1,182	-51
12 months or longer, Fair Value	3,364	0
12 months or longer, Unrealized Loss	-337	0
US Government-sponsored Enterprises Debt Securities [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	6,640	'
Unrealized Loss	-425	'
Less than 12 months, Fair Value	5,752	'
Less than 12 months, Unrealized Loss	-321	'
12 months or longer, Fair Value	888	'
12 months or longer, Unrealized Loss	-104	'
State and municipal bonds [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	203,970	11,234
Unrealized Loss	-7,927	-94
Less than 12 months, Fair Value	184,401	9,232
Less than 12 months, Unrealized Loss	-6,640	-65
12 months or longer, Fair Value	19,569	2,002
12 months or longer, Unrealized Loss	-1,287	-29
Corporate debt [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	349,277	90,154
Unrealized Loss	-13,744	-1,543
Less than 12 months, Fair Value	324,510	81,878
Less than 12 months, Unrealized Loss	-12,061	-1,377
12 months or longer, Fair Value	24,767	8,276
12 months or longer, Unrealized Loss	-1,683	-166
Residential mortgage-backed securities [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	93,608	10,721
Unrealized Loss	-2,855	-210
Less than 12 months, Fair Value	84,045	10,029
Less than 12 months, Unrealized Loss	-2,393	-205
12 months or longer, Fair Value	9,563	692
12 months or longer, Unrealized Loss	-462	-5
Agency commercial mortgage-backed securities [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	11,658	1,643
Unrealized Loss	-136	-25
Less than 12 months, Fair Value	11,082	498
Less than 12 months, Unrealized Loss	-116	-2
12 months or longer, Fair Value	576	1,145
12 months or longer, Unrealized Loss	-20	-23
Other commercial mortgage-backed securities [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	11,153	2,100
Unrealized Loss	-167	-5
Less than 12 months, Fair Value	10,215	1,103
Less than 12 months, Unrealized Loss	-159	-1
12 months or longer, Fair Value	938	997
12 months or longer, Unrealized Loss	-8	-4
Other asset-backed securities [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	25,539	10,746
Unrealized Loss	-324	-601
Less than 12 months, Fair Value	21,804	7,707
Less than 12 months, Unrealized Loss	-77	-20
12 months or longer, Fair Value	3,735	3,039
12 months or longer, Unrealized Loss	-247	-581
Debt Securities [Member]	'	'
Investments held in an unrealized loss position	'	'
Fair Value	749,513	130,671
Unrealized Loss	-27,097	-2,529
Less than 12 months, Fair Value	686,113	114,520
Less than 12 months, Unrealized Loss	-22,949	-1,721
12 months or longer, Fair Value	63,400	16,151
12 months or longer, Unrealized Loss	($4,148)	($808)

Investments_Details_5

Investments (Details 5) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Investment Income	'	'	'
Investment fees and expenses	($6,798)	($6,609)	($6,578)
Net investment income	129,265	136,094	140,956
Fixed maturities [Member]	'	'	'
Net Investment Income	'	'	'
Interest and Dividend Income, Operating	122,065	133,088	140,897
Equities [Member]	'	'	'
Net Investment Income	'	'	'
Interest and Dividend Income, Operating	9,454	6,947	1,808
Short-term Investments and Other Invested [Member]	'	'	'
Net Investment Income	'	'	'
Interest and Dividend Income, Operating	2,584	660	2,812
Business owned life insurance [Member]	'	'	'
Net Investment Income	'	'	'
Interest and Dividend Income, Operating	$1,960	$2,008	$2,017

Investments_Details_6

Investments (Details 6) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Total other-than-temporary impairment losses:	'	'	'
Other-than-temporary impairment (OTTI) losses	($71)	($1,566)	($5,189)
Portion of OTTI losses recognized in (reclassified from) other comprehensive income before taxes	0	-201	-823
Net impairment losses recognized in earnings	-71	-1,767	-6,012
Gross realized gains, available-for-sale securities	18,130	18,645	14,625
Gross realized (losses), available-for-sale securities	-7,031	-2,076	-1,754
Net realized gains (losses), trading securities	20,444	1,485	2,212
Change in unrealized holding gains (losses), trading securities	35,507	12,673	-3,188
Decrease (increase) in the fair value of liabilities carried at fair value	0	-1,245	111
Other	925	1,148	0
Total net realized investment gains (losses)	67,904	28,863	5,994
State and municipal bonds [Member]	'	'	'
Total other-than-temporary impairment losses:	'	'	'
Other-than-temporary impairment (OTTI) losses	-71	0	0
Residential mortgage-backed securities [Member]	'	'	'
Total other-than-temporary impairment losses:	'	'	'
Other-than-temporary impairment (OTTI) losses	0	-557	-782
Portion of OTTI losses recognized in (reclassified from) other comprehensive income before taxes	0	-201	-823
Corporate debt [Member]	'	'	'
Total other-than-temporary impairment losses:	'	'	'
Other-than-temporary impairment (OTTI) losses	0	-878	-505
Other Investments [Member]	'	'	'
Total other-than-temporary impairment losses:	'	'	'
Other-than-temporary impairment (OTTI) losses	0	-131	-3,827
High yield asset backed securities [Member]	'	'	'
Total other-than-temporary impairment losses:	'	'	'
Other-than-temporary impairment (OTTI) losses	$0	$0	($75)

Investments_Details_7

Investments (Details 7) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cumulative credit losses recorded in earnings related to impaired debt securities	'	'	'
Accumulated credit losses related to impaired debt securities, Beginning Balance	$3,301	$5,870	$4,446
OTTI has been previously recognized	0	268	1,424
Securities sold during the period (realized)	-3,218	-2,837	0
Accumulated credit losses related to impaired debt securities, Ending Balance	$83	$3,301	$5,870

Investments_Details_8

Investments (Details 8) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Information regarding sales and purchases of available-for-sale securities	'	'	'
Proceeds from sales (exclusive of maturities and paydowns)	$593,300,000	$500,200,000	$424,800,000
Purchases	$519,161,000	$646,198,000	$782,555,000

Investments_Details_Textual

Investments (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
	Affiliate
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of investment affiliates exceeding shareholder's equity ten percent threshold limit	0	'
Threshold limit of investments based on shareholders' equity	10.00%	'
Securities on deposit with state insurance departments	$36,300,000	'
Business owned life insurance cost	33,000,000	'
Investment in unconsolidated subsidiaries	214,236,000	121,049,000
Effect of conversion to equity method, total	10,500,000	'
Effect of conversion to equity method, prior years	8,400,000	'
Tax Credit Partnerships Almost 100% Ownership [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of tax credit partnerships almost 100% ownership percentage	2	'
Investment in unconsolidated subsidiaries	62,400,000	'
Tax Credit Partnerships Less Than 20% Ownership [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment in unconsolidated subsidiaries	79,800,000	'
Maximum [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Period for federal home loan bank stock liquidation process	'5 years	'
Maximum [Member] | Tax Credit Partnerships Almost 100% Ownership [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Percentage Ownership	100.00%	'
Maximum [Member] | Tax Credit Partnerships Less Than 20% Ownership [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Percentage Ownership	20.00%	'
Non Government-Backed [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of debt securities in unrealized loss position	714	110
Debt securities in unrealized loss position as percentage of total debt securities held	26.30%	4.40%
Number of issuers in unrealized loss position	516	93
Single greatest unrealized loss position	400,000	600,000
Second greatest unrealized loss position	$400,000	$200,000

Reinsurance_Details

Reinsurance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Summary of the effect of reinsurance on premiums written and earned	'		'		'
Direct premiums written	$566,745		$536,318		$565,746
Premiums earned	568,629	[1]	558,200	[1]	570,891	[1]
Assumed premiums written	802		113		149
Premiums assumed	804	[1]	116	[1]	154	[1]
Ceded premiums written	-42,365		-8,133		-7,388
Premiums ceded	-41,514	[1]	-7,652	[1]	-5,630	[1]
Premiums written, net	525,182		528,298		558,507
Net premiums earned	$527,919	[1]	$550,664	[1]	$565,415	[1]
[1]	All of ProAssurance’s premiums are related to property and liability coverages.

Reinsurance_Details_Textual_1

Reinsurance (Details Textual 1) (USD $)	0 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reinsurance Retention Policy [Line Items]	'	'	'	'
Reinsurance retention policy, amount retained	$1,000,000	'	'	'
Premiums written, net	'	525,182,000	528,298,000	558,507,000
Minimum [Member]	'	'	'	'
Reinsurance Retention Policy [Line Items]	'	'	'	'
Retention percentage within retained layer	'	90.00%	'	'
Maximum [Member]	'	'	'	'
Reinsurance Retention Policy [Line Items]	'	'	'	'
Retention percentage within retained layer	'	100.00%	'	'
Reinsurance percentage retained within excess layer	'	5.00%	'	'
Other Reinsurance Arrangements [Member]	'	'	'	'
Reinsurance Retention Policy [Line Items]	'	'	'	'
Premiums written	'	37,500,000	'	'
Premiums written, net	'	20,200,000	'	'
Medical Technology and Life Sciences [Member]	'	'	'	'
Reinsurance Retention Policy [Line Items]	'	'	'	'
Retention percentage within retained layer	'	100.00%	'	'
Reinsurance retention policy, amount retained	'	$1,000,000	'	'
Medical Technology and Life Sciences [Member] | Minimum [Member]	'	'	'	'
Reinsurance Retention Policy [Line Items]	'	'	'	'
Reinsurance percentage retained within excess layer	'	5.00%	'	'
Medical Technology and Life Sciences [Member] | Maximum [Member]	'	'	'	'
Reinsurance Retention Policy [Line Items]	'	'	'	'
Reinsurance percentage retained within excess layer	'	33.00%	'	'

Reinsurance_Details_Textual_2

Reinsurance (Details Textual 2) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	reinsurer
Ceded Credit Risk [Line Items]	'	'	'
Premium ceded reduction amount	$16,400,000	$34,300,000	$30,600,000
Amount due from reinsurers total	237,900,000	'	'
Amounts due from individual reinsurers exceeding shareholders' equity threshold amount	0	'	'
Individual reinsurer balances as percentage of shareholder's equity, maximum	5.00%	'	'
Termination of outstanding reinsurance arrangements in cash	'	'	4,300,000
Decrease in reinsurance recoverable due to commutation	'	'	4,000,000
Decrease in reinsurance premiums payable due to commutation	'	'	5,600,000
Number of major reinsurers	4	'	'
Allowance for reinsurance receivables	0	0	'
Loss on uncollectible accounts in the period	0	0	0
Ceded Credit Risk, Secured [Member]	'	'	'
Ceded Credit Risk [Line Items]	'	'	'
Amount of reinsurance recoverables collateralized by letters of credit	25,000,000	'	'
Major Reinsurers [Member]	'	'	'
Ceded Credit Risk [Line Items]	'	'	'
Amount due from reinsurers total	92,100,000	'	'
Minimum [Member]	'	'	'
Ceded Credit Risk [Line Items]	'	'	'
Major reinsurer threshold	$20,000,000	'	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred tax assets	'	'
Unpaid loss discount	$51,879	$57,811
Unearned premium adjustment	21,861	20,497
Compensation related	18,172	14,634
Intangibles	2,074	2,214
Total deferred tax assets	93,986	95,156
Deferred tax liabilities	'	'
Deferred acquisition costs	10,150	8,112
Unrealized gains on investments, net	32,127	78,284
Fixed assets	4,166	5,630
Basis differentials–investments	31,247	3,029
Intangibles	13,238	14,311
Other	1,301	375
Total deferred tax liabilities	92,229	109,741
Net deferred tax assets (liabilities)	$1,757	($14,585)

Income_Taxes_Details_1

Income Taxes (Details 1) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of unrecognized tax benefits	'	'	'
Balance at January 1	$4,823	$18,585	$8,344
(Decreases) for tax positions taken during the current year	0	-10,206	0
Increases for tax positions taken during prior years	0	0	18,585
(Decreases) for tax positions taken during prior years	0	-3,556	0
(Decreases) relating to settlements with taxing authorities	0	0	-8,344
Balance at December 31	$4,823	$4,823	$18,585

Income_Taxes_Details_2

Income Taxes (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of expected income tax expense to actual income tax expense	'	'	'
Computed “expected” tax expense	$139,005	$138,588	$145,109
Tax-exempt income	-14,509	-14,374	-13,793
Tax credits	-17,888	-10,005	-5,654
Non-taxable gain on acquisition	-11,310	0	0
Other	4,338	6,287	1,840
Total income tax expense (benefit)	$99,636	$120,496	$127,502

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	0 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'	'
Capital loss carryforwards	$0	$0	'	'
Amount of available net operating loss (NOL) carryforwards	0	0	'	'
Estimate of possible liability increase	130,000,000	'	'	'
Expected refund from settlement with IRS	9,600,000	9,600,000	'	'
Decreases relating to settlements with taxing authorities	'	0	0	8,344,000
Income taxes receivable	27,000,000	27,000,000	'	'
Accrued income taxes	'	'	20,000,000	'
Unrecognized Tax Benefits, Interest on Income Taxes Expense	'	0	500,000	800,000
Accrued liability for interest and penalties	1,300,000	1,300,000	1,400,000	'
Percentage of income before income taxes included in expected income tax expense	'	35.00%	35.00%	35.00%
Deferred tax assets, alternative minimum tax	$0	$0	'	'

Deferred_Policy_Acquisition_Co1

Deferred Policy Acquisition Costs (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Insurance [Abstract]	'	'	'
Amortization of deferred policy acquisition costs	$59.10	$57	$59.60

Reserve_for_Losses_and_Loss_Ad2

Reserve for Losses and Loss Adjustment Expenses (Details) (USD $)

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

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, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Insurance [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

Minimum period for claims resolution

'

'

'

'

'

'

'

'

'5 years

'

'

'

Liability For unpaid claims and claims adjustment expense incurred claims prior years accident years

'

'

'

'

'

'

'

'

'2005 through 2011

'2004 through 2009

'2004 through 2008

'

Summary of reserve for losses and loss adjustment expenses

'

'

'

'

'

'

'

'

'

'

'

'

Balance, beginning of year

'

'

'

$2,054,994

'

'

'

$2,247,772

$2,054,994

$2,247,772

$2,414,100

'

Receivable from reinsurers on unpaid losses and loss adjustment expenses

247,518

'

'

'

191,645

'

'

'

247,518

191,645

247,658

277,436

Net balance, beginning of year

'

'

'

1,863,349

'

'

'

2,000,114

1,863,349

2,000,114

2,136,664

'

Net reserves acquired from acquisitions

'

'

'

'

'

'

'

'

126,007

22,464

0

'

Net losses:

'

'

'

'

'

'

'

'

'

'

'

'

Current year

116,689

110,987

109,109

110,726

119,539

106,621

108,134

117,656

447,510

451,951

488,152

'

Favorable development of reserves established in prior years, net

-81,799

-49,350

-38,500

-53,100

-114,531

-50,000

-60,050

-47,457

-222,749

-272,038

-325,865

'

Total

'

'

'

'

'

'

'

'

224,761

179,913

162,287

'

Paid related to:

'

'

'

'

'

'

'

'

'

'

'

'

Current year

'

'

'

'

'

'

'

'

-43,616

-38,439

-34,240

'

Prior years

'

'

'

'

'

'

'

'

-345,197

-300,703

-264,597

'

Total paid

'

'

'

'

'

'

'

'

-388,813

-339,142

-298,837

'

Net balance, end of year

1,825,304

'

'

'

1,863,349

'

'

'

1,825,304

1,863,349

2,000,114

'

Balance, end of year

$2,072,822

'

'

'

$2,054,994

'

'

'

$2,072,822

$2,054,994

$2,247,772

'

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of future minimum lease payments for operating leases	'
2014	$3,039
2015	2,750
2016	2,553
2017	2,394
Thereafter	9,175
Total minimum lease payments	$19,911

Commitments_and_Contingencies_2

Commitments and Contingencies (Details Textual)	12 Months Ended					0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
	USD ($)	USD ($)	USD ($)	GBP (£)	Non-Public Equity Funds [Member]	FAL Standby Letter of Credit [Member]	FAL Standby Letter of Credit [Member]	FAL Standby Letter of Credit [Member]	Maximum [Member]
					USD ($)	USD ($)	GBP (£)	Prime Rate [Member]	FAL Standby Letter of Credit [Member]
Other Commitment, Fiscal Year Maturity [Abstract]	'	'	'	'	'	'	'	'	'
Other commitment	'	'	'	'	$164.20	'	'	'	'
Other commitment, due in 2014	'	'	'	'	49.6	'	'	'	'
Other commitment, due in 2015 and 2016	'	'	'	'	68.9	'	'	'	'
Other commitment, due in 2017	'	'	'	'	26.8	'	'	'	'
Other commitment, due thereafter	'	'	'	'	18.9	'	'	'	'
Letters of credit outstanding	'	'	'	'	'	69.3	41.9	'	'
FAL Deposit assets	8.7	'	'	'	'	'	'	'	'
Letter of Credit, expiration date	'	'	'	'	'	'4 years	'4 years	'	'
Variable interest rate spread of letter of credit	'	'	'	'	'	'	'	4.00%	'
Commitment fee percentages	'	'	'	'	'	0.50%	0.50%	'	1.88%
Line of credit extended to Lloyd's Syndicate, lending capacity	17	'	'	10	'	'	'	'	'
Line of credit extended to Lloyd's Syndicate, interest rate	8.50%	'	'	'	'	'	'	'	'
Amount receivable under line of credit extended to Lloyd's Syndicate	1.7	'	'	1	'	'	'	'	'
Rent expense	$3.20	$2.70	$3.40	'	'	'	'	'	'

Longterm_Debt_Details

Long-term Debt (Details) (USD $)

12 Months Ended

0 Months Ended

0 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Apr. 15, 2011

Apr. 15, 2011

Apr. 15, 2011

Apr. 15, 2011

Apr. 15, 2011

Sep. 28, 2012

Sep. 28, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Revolving credit agreement [Member]

Senior notes due 2023 [Member]

Senior notes due 2023 [Member]

Senior notes due 2023 [Member]

Note Payable Due 2019 [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Base Rate [Member]

Prime Rate [Member]

Federal Funds Rate [Member]

One Month LIBOR [Member]

Minimum [Member]

Maximum [Member]

Senior Notes [Member]

Senior Notes [Member]

US Treasury Note Rate [Member]

Notes Payable [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Senior Notes [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate at period end

'

'

'

'

'

'

'

'

'

'

'

'

5.30%

'

'

'

Outstanding long-term debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

$250,000,000

$125,000,000

'

$0

$125,000,000

'

'

'

'

'

'

'

$250,000,000

$0

'

'

Current Revolving credit capacity

'

'

'

150,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Commitment fee percentages

'

'

'

'

'

'

'

'

'

'

0.15%

0.30%

'

'

'

'

Description of variable rate basis

'

'

'

'

'

'

'base rate

'Prime rate

'Federal Funds

'one month LIBOR

'

'

'

'

'

'

Variable interest rate of long term debt

'

'

'

'

'

'

'

'

0.50%

1.00%

'

'

'

'

0.40%

'

Line of credit facility, interest rate adjustment

'

'

'

'

'

'

'

'

'

'

0.00%

1.88%

'

'

'

'

Maximum allowable consolidated funded indebtedness ratio

'

'

'

'

'

0.35

'

'

'

'

'

'

'

'

'

'

Net worth requirement, sum of Consolidated Net Worth

'

'

'

'

'

75.00%

'

'

'

'

'

'

'

'

'

'

Net worth requirement, percentage of consolidated net income earned

'

'

'

'

'

50.00%

'

'

'

'

'

'

'

'

'

'

Net worth requirement, percentage of net cash proceeds from issuance of stock

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

Loss on extinguishment of debt

$0

$2,163,000

$0

'

'

'

'

'

'

'

'

'

'

'

'

$2,200,000

Shareholders_Equity_Details

Shareholders' Equity (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	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, 2013	Dec. 31, 2012	Dec. 31, 2011
Reclassification adjustments related to available-for-sale securities	'	'	'	'	'	'	'	'	'	'	'
Net realized investment gains (losses) included in the calculation of net income	'	'	'	'	'	'	'	'	$67,904	$28,863	$5,994
Total amounts reclassified, before tax effect	'	'	'	'	'	'	'	'	397,159	395,966	414,598
Tax effect (at 35%)	'	'	'	'	'	'	'	'	-99,636	-120,496	-127,502
Net income	70,864	63,357	50,451	112,850	101,266	60,106	58,453	55,645	297,523	275,470	287,096
Reclassifications from accumulated other comprehensive income to net income, available for sale securities [Member]	'	'	'	'	'	'	'	'	'	'	'
Reclassification adjustments related to available-for-sale securities	'	'	'	'	'	'	'	'	'	'	'
Total amounts reclassified, before tax effect	'	'	'	'	'	'	'	'	11,028	14,933	10,686
Tax effect (at 35%)	'	'	'	'	'	'	'	'	-3,860	-5,227	-3,740
Net income	'	'	'	'	'	'	'	'	7,168	9,706	6,946
Reclassifications from accumulated other comprehensive income to net income, available for sale securities [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]	'	'	'	'	'	'	'	'	'	'	'
Reclassification adjustments related to available-for-sale securities	'	'	'	'	'	'	'	'	'	'	'
Net realized investment gains (losses) included in the calculation of net income	'	'	'	'	'	'	'	'	11,375	17,350	13,101
Reclassifications from accumulated other comprehensive income to net income, available for sale securities [Member] | Accumulated Other-than-Temporary Impairment [Member]	'	'	'	'	'	'	'	'	'	'	'
Reclassification adjustments related to available-for-sale securities	'	'	'	'	'	'	'	'	'	'	'
Net realized investment gains (losses) included in the calculation of net income	'	'	'	'	'	'	'	'	($347)	($2,417)	($2,415)

Shareholders_Equity_Details_Te

Shareholders' Equity (Details Textual) (USD $)

0 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

3 Months Ended

0 Months Ended

1 Months Ended

Dec. 27, 2012

Feb. 28, 2013

Feb. 29, 2012

Feb. 28, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Sep. 30, 2011

Dec. 31, 2012

Dec. 27, 2012

Dec. 31, 2012

Dec. 31, 2013

Stock Split [Member]

ProAssurance Corporation 2011 Stock Ownership Plan Particpant Accounts [Member]

ProAssurance Corporation 2011 Stock Ownership Plan Particpant Accounts [Member]

ProAssurance Corporation 2011 Stock Ownership Plan Particpant Accounts [Member]

Quarterly Q3 2011 through Q3 2012 [Member]

Quarterly Q4 2012 through Q3 2013 [Member]

Dividends Declared, Special [Member]

Dividends Declared, Special [Member]

Retained Earnings, Unappropriated [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common shares, shares authorized

'

'

'

'

100,000,000

100,000,000

100,000,000

'

'

'

'

'

'

'

'

'

'

'

Authorized preferred stock (in shares)

'

'

'

'

50,000,000

50,000,000

50,000,000

'

'

'

'

'

'

'

'

'

'

'

Quarterly dividend declared, per share

'

'

'

'

$0.30

$1.05

$3.13

$0.25

'

'

'

'

'

$0.13

$0.25

$2.50

$2.50

'

Dividends payable

'

'

'

'

$18,400,000

$18,400,000

'

'

'

'

'

'

'

'

'

'

'

'

Equity attributable to parent

'

'

'

'

2,394,414,000

2,394,414,000

2,270,580,000

2,164,453,000

1,855,863,000

'

'

'

'

'

'

'

'

572,000,000

Total authorizations which remain available for use

'

'

'

'

202,600,000

202,600,000

'

'

'

'

'

'

'

'

'

'

'

'

Repurchased common shares (in shares)

'

'

'

'

'

700,000

0

700,000

'

'

'

'

'

'

'

'

'

'

Treasury stock reissued (in shares)

'

'

'

'

'

'

'

'

'

7,700,000

25,000

23,000

18,000

'

'

'

'

'

Stock split, conversion ratio

2

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

'

'

Bonus compensation shares issued (in shares)

'

41,000

37,000

40,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Authorization common shares for the issuance under incentive compensation plans (in shares)

'

'

'

'

3,000,000

3,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Authorized common shares for the issuance of outstanding shares (in shares)

'

'

'

'

800,000

800,000

'

'

'

'

'

'

'

'

'

'

'

'

Other than temporary impairment, available-for-sale

'

'

'

'

500,000

500,000

900,000

'

'

'

'

'

'

'

'

'

'

'

Percentage of income before income taxes included in expected income tax expense

'

'

'

'

'

35.00%

35.00%

35.00%

'

'

'

'

'

'

'

'

'

'

Common shares reacquired (in shares)

'

'

'

'

'

$32,454,000

'

$21,005,000

'

'

'

'

'

'

'

'

'

'

ShareBased_Payments_Details

Share-Based Payments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods	'	'	'
Share-based compensation expense	$9,242,000	$8,639,000	$7,119,000
Tax benefit recognized	3,200,000	3,000,000	2,500,000
Unrecognized Compensation Cost, Amount	11,700,000	'	'
Stock Options [Member]	'	'	'
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods	'	'	'
Share-based compensation expense	0	0	100,000
Unrecognized Compensation Cost, Amount	0	'	'
Restricted Stock Units (RSUs) [Member]	'	'	'
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods	'	'	'
Share-based compensation expense	1,600,000	1,600,000	1,300,000
Unrecognized Compensation Cost, Amount	2,100,000	'	'
Unrecognized Compensation Cost, remaining recognition period	'1 year 8 months 12 days	'	'
Performance Shares Units [Member]	'	'	'
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods	'	'	'
Share-based compensation expense	7,100,000	6,700,000	5,600,000
Unrecognized Compensation Cost, Amount	8,100,000	'	'
Unrecognized Compensation Cost, remaining recognition period	'1 year 8 months 12 days	'	'
Purchase Match Units [Member]	'	'	'
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods	'	'	'
Share-based compensation expense	500,000	300,000	100,000
Unrecognized Compensation Cost, Amount	$1,500,000	'	'
Unrecognized Compensation Cost, remaining recognition period	'2 years 2 months 12 days	'	'

ShareBased_Payments_Details_1

Share-Based Payments (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of activity for stock options	'	'	'
Stock Options, Outstanding, Beginning of the year (in shares)	20,302	1,014,661	1,430,105
Stock Options, Outstanding, Granted (in shares)	0	0	0
Stock Options, Outstanding, Exercised (in shares)	-2,220	-994,148	-412,695
Stock Options, Outstanding, Forfeited or Expired (in shares)	0	-211	-2,749
Stock Options, Outstanding, Ending of the year (in shares)	18,082	20,302	1,014,661
Stock Options, Outstanding, Exercisable at end of year (in shares)	18,082	20,302	959,889
Stock Options, Outstanding at end of year, Vested or Expected to Vest (in shares)	18,082	20,302	1,014,064
Summary of activity for stock options, weighted average exercise price	'	'	'
Stock Options, Outstanding, Weighted Average Exercise Price, Beginning of the year (USD per share)	$23.15	$22.76	$21.85
Stock Options, Outstanding, Weighted Average Exercise Price, Granted (USD per share)	$0	$0	$0
Stock Options, Outstanding, Weighted Average Exercise Price ,Exercised (USD per share)	$24.28	$22.75	$19.61
Stock Options, Outstanding, Weighted Average Exercise Price, Forfeited and Expired (USD per share)	$0	$25.67	$25.36
Stock Options, Outstanding, Weighted Average Exercise Price, End of the Period (USD per share)	$23	$23.15	$22.76
Stock Options, Outstanding, Weighted Average Exercise Price, Exercisable (USD per share)	$23	$23.15	$22.59
Stock Options, Outstanding at end of year, Weighted Average Exercise Price, vested or expected to vest (USD per share)	$23	$23.15	$22.75

ShareBased_Payments_Details_2

Share-Based Payments (Details 2) (Restricted Stock Units (RSUs) [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock Units (RSUs) [Member]	'	'	'
Summary Activity for restricted share units, number of shares	'	'	'
Beginning non-vested balance (in shares)	157,212	167,236	120,478
Granted (in shares)	39,400	51,864	52,256
Forfeited (in shares)	-603	-2,823	-5,075
Vested (in shares)	-57,239	-59,065	-423
Ending non-vested balance (in shares)	138,770	157,212	167,236
Summary Activity for restricted share units, weighted average grant date fair value	'	'	'
Beginning balance, weighted average grant date fair value per share (USD per share)	$31.94	$25.52	$23.88
Granted, weighted average grant date fair value per share (USD per share)	$46.97	$42.22	$29.27
Forfeited, weighted average grant date fair value per share (USD per share)	$35.91	$35.23	$25.38
Vested and released, weighted average grant date fair value per share (USD per share)	$25.25	$22.61	$22.56
Ending balance, weighted average grant date fair value per share (USD per share)	$38.92	$31.94	$25.52

ShareBased_Payments_Details_3

Share-Based Payments (Details 3) (Performance Shares Units [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Performance Shares Units [Member]	'	'	'
Summary Activity for restricted share units, number of shares	'	'	'
Beginning non-vested balance (in shares)	552,417	522,599	493,661
Granted (in shares)	145,580	212,205	196,186
Forfeited (in shares)	-17,043	-20,492	-15,804
Vested (in shares)	-194,274	-161,895	-151,444
Ending non-vested balance (in shares)	486,680	552,417	522,599
Summary Activity for restricted share units, weighted average grant date fair value	'	'	'
Beginning balance, weighted average grant date fair value per share (USD per share)	$33.21	$26.36	$24.56
Granted, weighted average grant date fair value per share (USD per share)	$46.97	$42.22	$30.30
Forfeited, weighted average grant date fair value per share (USD per share)	$38.90	$31.44	$26.28
Vested and released, weighted average grant date fair value per share (USD per share)	$26.39	$23.13	$25.61
Ending balance, weighted average grant date fair value per share (USD per share)	$39.86	$33.21	$26.36
Common shares issued due to vesting of awards	135,044	114,884	112,822

Share_Based_Payments_Details_4

Share Based Payments (Details 4) (Employee Awards [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Awards [Member]	'	'	'
Summary Activity for restricted share units, number of shares	'	'	'
Beginning non-vested balance (in shares)	40,985	18,900	0
Granted (in shares)	25,151	23,799	19,016
Forfeited (in shares)	-2,456	-1,610	-116
Vested (in shares)	-555	-104	0
Ending non-vested balance (in shares)	63,125	40,985	18,900
Summary Activity for restricted share units, weighted average grant date fair value	'	'	'
Beginning balance, weighted average grant date fair value per share (USD per share)	$39.85	$36.20	$0
Granted, weighted average grant date fair value per share (USD per share)	$43.57	$42.59	$36.20
Forfeited, weighted average grant date fair value per share (USD per share)	$40.71	$37.72	$36.20
Vested and released, weighted average grant date fair value per share (USD per share)	$36.33	$36.20	$0
Ending balance, weighted average grant date fair value per share (USD per share)	$41.34	$39.85	$36.20

ShareBased_Payments_Details_Te

Share-Based Payments (Details Textual) (USD $)

0 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

12 Months Ended

Dec. 27, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 27, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Award_Type

Installment

Dividends Declared, Special [Member]

Dividends Declared, Special [Member]

Performance Shares Units [Member]

Performance Shares Units [Member]

Performance Shares Units [Member]

Stock Options [Member]

Management Awards [Member]

Management Awards [Member]

Employee Awards [Member]

Minimum [Member]

Maximum [Member]

Incentive_Plan

Award_Type

Performance Shares Units [Member]

Performance Shares Units [Member]

Incentive_Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of share-based compensation plans

'

4

4

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of award types

'

4

4

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected average period

'

'

'

'

'

'

'

'3 years

'

'

'

'3 years

'

'3 years

'

'

Cash dividends declared per common share

'

$0.30

$1.05

$3.13

$0.25

$2.50

$2.50

'

'

'

'

'

'

'

'

'

Stock split, conversion ratio

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of installments for stock options

'

'

5

'

'

'

'

'

'

'

'

'

'

'

'

'

Period of options granted

'

'

'

'

'

'

'

'

'

'

'10 years

'

'

'

'

'

Aggregate grant date fair value of options vested in period

'

'

'

$900,000

$900,000

'

'

'

'

'

'

'

'

'

'

'

The aggregate grant date intrinsic value of options exercised

'

'

100,000

19,800,000

5,800,000

'

'

'

'

'

'

'

'

'

'

'

Aggregate intrinsic value of stock options outstanding

'

500,000

500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average remaining contractual term of stock options

'

'

'2 years 11 months 5 days

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash proceeds from stock option exercises

'

'

0

0

0

'

'

'

'

'

'

'

'

'

'

'

The aggregate grant date fair value of Employee awards

'

'

'

'

'

'

'

5,100,000

3,700,000

3,900,000

'

1,400,000

1,300,000

'

'

'

The percentage of award vest

'

'

'

'

'

'

'

125.00%

'

'

'

'

'

'

75.00%

125.00%

Aggregate intrinsic value

'

'

'

'

'

'

'

9,100,000

7,200,000

5,300,000

'

2,700,000

2,600,000

'

'

'

Annual contribution for the purchase of shares

'

'

'

'

'

'

'

'

'

'

'

'

'

$5,000

'

'

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (Variable Interest Entity, Not Primary Beneficiary [Member], USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other Investments [Member]	'	'
Variable Interest Entity [Line Items]	'	'
Variable interest entity nonconsolidated assets	$27.30	$25.10
Variable interest entity, maximum loss exposure	27.3	'
Equity Method Investments [Member]	'	'
Variable Interest Entity [Line Items]	'	'
Variable interest entity nonconsolidated assets	49.5	33.7
Variable interest entity, maximum loss exposure	$49.50	'

Benefit_Plans_Details

Benefit Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]	'	'	'
Percentage of benefit plan contribution by employer, Minimum	5.00%	'	'
Percentage of benefit plan contribution by employer, Maximum	10.00%	'	'
ProAssurance incurred expense related to the savings and retirement plans	$9.80	$5.10	$4.30
ProAssurance incurred expense related to the ProAssurance Plan	0.2	0.2	0.2
ProAssurance deferred compensation liabilities total	$13.10	$11.10	'

Statutory_Accounting_and_Divid2

Statutory Accounting and Dividend Restrictions (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated Net Income Related to Statutory Accounting	'	'	'
Statutory Net Earnings	$256,000,000	$312,000,000	$291,000,000
Statutory Capital and Surplus	1,642,000,000	1,499,000,000	'
Assets held at insurance subsidiaries	1,800,000,000	'	'
Dividend payments from insurance subsidiaries	$243,000,000	'	'

Quarterly_Results_of_Operation2

Quarterly Results of Operations (Unaudited) (Details) (USD $)	3 Months Ended																12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	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, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of unaudited quarterly results of operations	'		'		'		'		'		'		'		'		'	'	'
Net premiums earned	$129,392		$133,598		$130,352		$134,578		$155,615		$127,125		$131,266		$136,659		$527,919	$550,664	$565,415
Net losses and loss adjustment expenses:	'		'		'		'		'		'		'		'		'	'	'
Current year	116,689		110,987		109,109		110,726		119,539		106,621		108,134		117,656		447,510	451,951	488,152
Prior year	-81,799		-49,350		-38,500		-53,100		-114,531		-50,000		-60,050		-47,457		-222,749	-272,038	-325,865
Net income	$70,864		$63,357		$50,451		$112,850		$101,266		$60,106		$58,453		$55,645		$297,523	$275,470	$287,096
Basic earnings per share (USD per share)	$1.15	[1]	$1.02	[1]	$0.82	[1]	$1.83	[1]	$1.65	[1]	$0.98	[1]	$0.95	[1]	$0.91	[1]	$4.82	$4.49	$4.70
Diluted earnings per share (USD per share)	$1.14	[1]	$1.02	[1]	$0.81	[1]	$1.82	[1]	$1.64	[1]	$0.97	[1]	$0.95	[1]	$0.90	[1]	$4.80	$4.46	$4.65
[1]	Quarterly and year-to-date computations of per share amounts are made independently; therefore, the sum of per share amounts for the quarters may not equal per share amounts for the respective year-to-date periods.

Schedule_I_Summary_of_Investme1

Schedule I - Summary of Investments-Other Than Investments In Related Parties (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	$3,799,019
Total Investments, Fair value	3,938,011
Total Investments, Amount which is presented in the balance sheet	3,941,045
U.S. Government or government agencies and authorities [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	197,057
Total Investments, Fair value	203,482
Total Investments, Amount which is presented in the balance sheet	203,482
States, municipalities and political subdivisions [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	1,116,060
Total Investments, Fair value	1,154,666
Total Investments, Amount which is presented in the balance sheet	1,154,666
Foreign Governments [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	5,141
Total Investments, Fair value	5,348
Total Investments, Amount which is presented in the balance sheet	5,348
Public utilities bonds [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	95,943
Total Investments, Fair value	98,501
Total Investments, Amount which is presented in the balance sheet	98,501
All other corporate bonds [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	1,220,604
Total Investments, Fair value	1,250,311
Total Investments, Amount which is presented in the balance sheet	1,250,311
Certificates of deposit [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	150
Total Investments, Fair value	6,993
Total Investments, Amount which is presented in the balance sheet	6,993
Mortgage-backed securities [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	391,301
Total Investments, Fair value	398,748
Total Investments, Amount which is presented in the balance sheet	398,748
Fixed Maturities [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	3,026,256
Total Investments, Fair value	3,118,049
Total Investments, Amount which is presented in the balance sheet	3,118,049
Banks, trusts and insurance companies, available for sale [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	0
Total Investments, Fair value	0
Total Investments, Amount which is presented in the balance sheet	0
Equity Securities, available-for-sale [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	0
Total Investments, Fair value	0
Total Investments, Amount which is presented in the balance sheet	0
Public utilities equity, trading [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	5,880
Total Investments, Fair value	7,107
Total Investments, Amount which is presented in the balance sheet	7,107
Banks, trusts and insurance companies, trading [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	68,596
Total Investments, Fair value	81,536
Total Investments, Amount which is presented in the balance sheet	81,536
Industrial, miscellaneous and all other, trading [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	128,832
Total Investments, Fair value	164,898
Total Investments, Amount which is presented in the balance sheet	164,898
Total Equity Securities, trading [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	203,308
Total Investments, Fair value	253,541
Total Investments, Amount which is presented in the balance sheet	253,541
Other long-term investments [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	320,850
Total Investments, Fair value	317,816
Total Investments, Amount which is presented in the balance sheet	320,850
Short-term Investments [Member]	'
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]	'
Total Investments, Recorded cost basis	248,605
Total Investments, Fair value	248,605
Total Investments, Amount which is presented in the balance sheet	$248,605

Schedule_II_Condensed_Financia2

Schedule II - Condensed Financial Information of Registrant (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Thousands, unless otherwise specified
Assets	'	'	'	'
Fixed maturities available for sale, at fair value	$3,118,049	$3,447,999	'	'
Equity securities, trading, at fair value	253,541	202,618	'	'
Short-term investments	248,605	71,737	'	'
Cash and cash equivalents	129,383	118,551	130,400	50,851
Restricted Cash	78,000	0	'	'
Other assets	329,979	234,286	'	'
Total Assets	5,150,891	4,876,578	'	'
Liabilities	'	'	'	'
Other liabilities	143,079	131,967	'	'
Long-term debt	250,000	125,000	'	'
Total Liabilities	2,756,477	2,605,998	'	'
Shareholders’ Equity:	'	'	'	'
Common stock	621	619	'	'
Total Shareholders’ Equity	2,394,414	2,270,580	2,164,453	1,855,863
Total Liabilities and Shareholders’ Equity	5,150,891	4,876,578	'	'
Parent Company [Member]	'	'	'	'
Assets	'	'	'	'
Investment in subsidiaries, at equity	2,005,420	2,092,445	'	'
Fixed maturities available for sale, at fair value	86,603	249,318	'	'
Equity securities, trading, at fair value	12,043	10,487	'	'
Short-term investments	191,991	4,366	'	'
Cash and cash equivalents	37,459	29,397	47,938	4,284
Restricted Cash	78,000	0	'	'
Due from subsidiaries	3,315	23,708	'	'
Other assets	255,313	7,747	'	'
Total Assets	2,670,144	2,417,468	'	'
Liabilities	'	'	'	'
Other liabilities	25,730	21,888	'	'
Long-term debt	250,000	125,000	'	'
Total Liabilities	275,730	146,888	'	'
Shareholders’ Equity:	'	'	'	'
Common stock	621	619	'	'
Other shareholders’ equity, including unrealized gains (losses) on securities of subsidiaries	2,393,793	2,269,961	'	'
Total Shareholders’ Equity	2,394,414	2,270,580	'	'
Total Liabilities and Shareholders’ Equity	$2,670,144	$2,417,468	'	'

Schedule_II_Condensed_Financia3

Schedule II - Condensed Financial Information of Registrant (Details 1) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	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, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'	'	'	'	'	'	'	'	'
Net investment income	'	'	'	'	'	'	'	'	$129,265	$136,094	$140,956
Equity in earnings (loss) of unconsolidated subsidiaries	'	'	'	'	'	'	'	'	7,539	-6,873	-9,147
Other income (loss)	'	'	'	'	'	'	'	'	7,551	7,106	13,566
Total revenues	'	'	'	'	'	'	'	'	740,178	715,854	716,784
Expenses	'	'	'	'	'	'	'	'	'	'	'
Interest expense	'	'	'	'	'	'	'	'	2,755	2,181	3,478
Total expenses	'	'	'	'	'	'	'	'	375,333	319,888	302,186
Income tax expense (benefit)	'	'	'	'	'	'	'	'	99,636	120,496	127,502
Net income	70,864	63,357	50,451	112,850	101,266	60,106	58,453	55,645	297,523	275,470	287,096
Parent Company [Member]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Net investment income	'	'	'	'	'	'	'	'	5,789	5,281	1,582
Equity in earnings (loss) of unconsolidated subsidiaries	'	'	'	'	'	'	'	'	0	-728	-2,479
Net realized investment gains (losses)	'	'	'	'	'	'	'	'	5,334	3,230	-141
Other income (loss)	'	'	'	'	'	'	'	'	170	54	101
Total revenues	'	'	'	'	'	'	'	'	11,293	7,837	-937
Expenses	'	'	'	'	'	'	'	'	'	'	'
Interest expense	'	'	'	'	'	'	'	'	2,747	1,534	1,833
Other expenses	'	'	'	'	'	'	'	'	13,213	8,870	7,855
Total expenses	'	'	'	'	'	'	'	'	15,960	10,404	9,688
Income (loss) before income tax expense (benefit) and equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	-4,667	-2,567	-10,625
Income tax expense (benefit)	'	'	'	'	'	'	'	'	-1,007	773	-3,209
Income (loss) before equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	-3,660	-3,340	-7,416
Equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	301,183	278,810	294,512
Net income	'	'	'	'	'	'	'	'	$297,523	$275,470	$287,096

Schedule_II_Condensed_Financia4

Schedule II - Condensed Financial Information of Registrant (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Cash provided (used) by operating activities	$38,602	$91,250	$159,364
Purchases of:	'	'	'
Equity securities trading	-87,604	-120,555	-117,208
Proceeds from sale or maturities of:	'	'	'
Fixed maturities, available for sale	970,708	926,221	789,709
Equity securities trading	123,645	54,670	50,386
Net decrease (increase) in short-term investments	-176,092	48,565	49,011
(Increase) decrease in restricted cash	-78,000	0	0
Funding for Syndicate 1729	-8,699	0	0
Cash received (paid) for other assets	-11,244	-4,410	-9,771
Net cash provided (used) by investing activities	-67,803	26,843	-49,611
Financing Activities	'	'	'
Proceeds from long-term debt	250,000	125,000	0
Principal repayment of debt	-127,183	-57,660	-325
Repurchase of common stock	-29,089	0	-21,005
Excess of tax benefit from share-based payment arrangements	2,128	7,022	1,711
Dividends to shareholders	-46,375	-200,118	-7,617
Other	-9,448	-4,186	-2,968
Net cash provided (used) by financing activities	40,033	-129,942	-30,204
Increase (decrease) in cash and cash equivalents	10,832	-11,849	79,549
Cash and cash equivalents at beginning of period	118,551	130,400	50,851
Cash and cash equivalents at end of period	129,383	118,551	130,400
Parent Company [Member]	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Cash provided (used) by operating activities	-26,319	3,601	-3,982
Purchases of:	'	'	'
Equity securities trading	-1,265	-364	-990
Proceeds from sale or maturities of:	'	'	'
Fixed maturities, available for sale	224,993	150,192	19,398
Equity securities trading	1,113	616	6,887
Net decrease (increase) in short-term investments	-187,625	58,657	-28,708
Dividends from subsidiaries	239,484	59,369	90,020
Contribution of capital to subsidiaries	0	-184,330	-12,500
Cash paid for acquisitions, net of cash received	-205,244	0	0
(Increase) decrease in restricted cash	-78,000	0	0
Funding for Syndicate 1729	-8,699	0	0
Cash received (paid) for other assets	-20	-1	-3,070
Net cash provided (used) by investing activities	-15,263	84,139	71,037
Financing Activities	'	'	'
Proceeds from long-term debt	250,000	125,000	0
Principal repayment of debt	-125,000	-32,992	0
Repurchase of common stock	-29,089	0	-21,005
Subsidiary payments for common shares and share-based compensation awarded to subsidiary employees	6,258	7,066	6,071
Excess of tax benefit from share-based payment arrangements	2,128	7,022	1,711
Dividends to shareholders	-46,375	-200,118	-7,617
Other	-8,278	-12,259	-2,561
Net cash provided (used) by financing activities	49,644	-106,281	-23,401
Increase (decrease) in cash and cash equivalents	8,062	-18,541	43,654
Cash and cash equivalents at beginning of period	29,397	47,938	4,284
Cash and cash equivalents at end of period	37,459	29,397	47,938
Significant non-cash transactions:	'	'	'
Securities transferred at fair value as dividends from subsidiaries	$69,011	$241,081	$197,224

Schedule_II_Condensed_Financia5

Schedule II - Condensed Financial Information of Registrant (Details 3) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Outstanding long-term debt	'	'
Long-term debt	$250,000	$125,000
Parent Company [Member]	'	'
Outstanding long-term debt	'	'
Long-term debt	250,000	125,000
Senior Notes [Member] | Senior notes due 2023 [Member]	'	'
Outstanding long-term debt	'	'
Long-term debt	250,000	0
Interest rate at period end	5.30%	'
Senior Notes [Member] | Senior notes due 2023 [Member] | Parent Company [Member]	'	'
Outstanding long-term debt	'	'
Long-term debt	250,000	0
Interest rate at period end	5.30%	'
Line of Credit [Member] | Revolving Credit Facility [Member]	'	'
Outstanding long-term debt	'	'
Long-term debt	0	125,000
Line of Credit [Member] | Revolving Credit Facility [Member] | Parent Company [Member]	'	'
Outstanding long-term debt	'	'
Long-term debt	$0	$125,000

Schedule_II_Condensed_Financia6

Schedule II - Condensed Financial Information of Registrant (Details Textual)

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jan. 02, 2014

Jan. 02, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Jan. 02, 2014

Jan. 02, 2013

USD ($)

GBP (£)

FAL Standby Letter of Credit [Member]

FAL Standby Letter of Credit [Member]

Eastern Insurance Holdings [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Parent Company [Member]

Parent Company [Member]

Parent Company [Member]

Parent Company [Member]

Parent Company [Member]

Parent Company [Member]

Parent Company [Member]

USD ($)

GBP (£)

USD ($)

Eastern Insurance Holdings [Member]

Eastern Insurance Holdings [Member]

USD ($)

USD ($)

USD ($)

GBP (£)

Eastern Insurance Holdings [Member]

Subsequent Event [Member]

Subsequent Event [Member]

USD ($)

USD ($)

Eastern Insurance Holdings [Member]

Eastern Insurance Holdings [Member]

USD ($)

Total purchase consideration

'

'

'

'

'

$205,000,000

'

'

'

'

'

'

$205,000,000

'

Voting interests acquired

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

100.00%

Third party conversion agent asset

'

'

'

'

205,000,000

'

'

'

'

'

'

205,000,000

'

'

Dividends paid to parent company by consolidated subsidiaries

'

'

'

'

'

'

'

308,500,000

300,500,000

287,200,000

'

'

'

'

Capital contribution

'

'

'

'

'

'

'

0

184,300,000

12,500,000

'

'

'

'

Letters of credit outstanding

'

'

69,300,000

41,900,000

'

'

'

'

'

'

'

'

'

'

FAL Deposit assets

8,700,000

'

'

'

'

'

'

8,700,000

'

'

'

'

'

'

Line of credit extended to Lloyd's Syndicate, lending capacity

17,000,000

10,000,000

'

'

'

'

'

17,000,000

'

'

10,000,000

'

'

'

Amount receivable under line of credit extended to Lloyd's Syndicate

$1,700,000

£ 1,000,000

'

'

'

'

'

$1,700,000

'

'

£ 1,000,000

'

'

'

Schedule_III_Supplementary_Ins1

Schedule III - Supplementary Insurance Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplementary Insurance Information [Abstract]	'	'	'
Deferred policy acquisition costs	$28,999	$23,179	$26,626
Reserve for losses and loss adjustment expenses	2,072,822	2,054,994	2,247,772
Unearned premiums	256,255	233,861	251,155
Net premiums earned	527,919	550,664	565,415
Net investment income	129,265	136,094	140,956
Losses and loss adjustment expenses incurred related to current year, net of reinsurance	447,510	451,951	488,152
Losses and loss adjustment expenses incurred related to prior year, net of reinsurance	222,749	272,038	325,865
Paid losses and loss adjustment expenses, net of reinsurance	388,813	339,142	298,837
Underwriting, policy acquisition and operating expenses:	'	'	'
Underwriting, policy acquisition and operating expenses:	59,063	57,007	59,591
Other underwriting, policy acquisition and operating expenses	88,754	78,624	76,830
Net premiums written	$525,182	$528,298	$558,507

Schedule_IV_Reinsurance_Detail

Schedule IV - Reinsurance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Property and Liability	'		'		'
Premiums earned	$568,629	[1]	$558,200	[1]	$570,891	[1]
Premiums ceded	-41,514	[1]	-7,652	[1]	-5,630	[1]
Premiums assumed	804	[1]	116	[1]	154	[1]
Net premiums earned	$527,919	[1]	$550,664	[1]	$565,415	[1]
Percentage of amount assumed to net	0.15%	[1]	0.02%	[1]	0.03%	[1]
[1]	All of ProAssurance’s premiums are related to property and liability coverages.