Platinum Underwriters (PTP) 10-Q 24 Oct 13 2013 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Oct. 17, 2013
Document and Entity Information [Abstract]
Entity Registrant Name	PLATINUM UNDERWRITERS HOLDINGS LTD
Entity Central Index Key	1171500
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		27,909,665
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	30-Sep-13

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investments:
Fixed maturity available-for-sale securities at fair value (amortized cost - $1,767,085 and $1,781,549, respectively)	$1,835,380	$1,941,685
Fixed maturity trading securities at fair value (amortized cost - $96,390 and $104,053, respectively)	102,604	112,813
Short-term investments	73,635	172,801
Total investments	2,011,619	2,227,299
Cash and cash equivalents	1,565,405	1,720,395
Accrued investment income	20,451	21,299
Reinsurance premiums receivable	133,769	128,517
Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses	3,525	3,899
Prepaid reinsurance premiums	5,120	2,661
Funds held by ceding companies	118,983	114,090
Deferred acquisition costs	32,378	28,112
Reinsurance deposit assets	78,179	50,693
Deferred tax assets	25,986	22,773
Other assets	13,844	13,565
Total assets	4,009,259	4,333,303
Liabilities
Unpaid losses and loss adjustment expenses	1,758,056	1,961,282
Unearned premiums	130,488	113,960
Debt obligations	250,000	250,000
Commissions payable	75,018	64,849
Other liabilities	96,767	48,678
Total liabilities	2,310,329	2,438,769
Shareholders' Equity
Common shares, $0.01 par value, 200,000,000 shares authorized 27,909,665 and 32,722,144 shares issued and outstanding, respectively	279	327
Additional paid-in capital	0	209,897
Accumulated other comprehensive income	57,390	137,690
Retained earnings	1,641,261	1,546,620
Total shareholders' equity	1,698,930	1,894,534
Total liabilities and shareholders' equity	$4,009,259	$4,333,303

Consolidated_Balance_Sheets_Un1

Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Per Share data, unless otherwise specified
Investments:
Fixed maturity available-for-sale securities, amortized cost	$1,767,085	$1,781,549
Fixed maturity trading securities, amortized cost	$96,390	$104,053
Shareholders' Equity
Common shares, par value (in dollars per share)	$0.01	$0.01
Common shares, authorized (in shares)	200,000,000	200,000,000
Common shares, issued (in shares)	27,909,665	32,722,144
Common shares, outstanding (in shares)	27,909,665	32,722,144

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue:
Net premiums earned	$135,360	$138,588	$405,146	$421,875
Net investment income (expense)	17,758	23,209	54,110	77,916
Net realized gains (losses) on investments	-306	22,982	24,698	70,299
Total other-than-temporary impairments	14	354	-600	263
Portion of impairment losses recognized in other comprehensive income	-79	-1,053	-1,402	-3,145
Net impairment losses on investments	-65	-699	-2,002	-2,882
Other income (expense)	1,426	-96	2,503	-766
Total revenue	154,173	183,984	484,455	566,442
Expenses:
Net losses and loss adjustment expenses	44,142	45,117	120,807	191,430
Net acquisition expenses	30,675	26,168	91,207	87,025
Operating expenses	20,672	19,966	59,695	56,645
Net foreign currency exchange losses (gains)	487	541	-592	763
Interest expense	4,782	4,775	14,341	14,321
Total expenses	100,758	96,567	285,458	350,184
Income (loss) before income taxes	53,415	87,417	198,997	216,258
Income tax expense (benefit)	15,130	2,553	24,342	10,575
Net income (loss)	38,285	84,864	174,655	205,683
Earnings (loss) per common share:
Basic earnings (loss) per common share (in dollars per share)	$1.34	$2.56	$5.71	$6.02
Diluted earnings (loss) per common share (in dollars per share)	$1.32	$2.54	$5.63	$5.98
Shareholder dividends:
Common shareholder dividends declared	$2,260	$2,630	$7,181	$8,137
Dividends declared per common share (in dollars per share)	$0.08	$0.08	$0.24	$0.24

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Comprehensive Income (Loss) [Abstract]
Net income (loss)	$38,285	$84,864	$174,655	$205,683
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	14	354	-600	263
Change in net unrealized gains and losses on all other securities	-7,622	24,211	-65,839	73,304
Total change in net unrealized gains and losses	-7,608	24,565	-66,439	73,567
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments	0	-22,710	-27,243	-70,607
Net impairment losses on investments	65	699	2,002	2,882
Total reclassifications to net income	65	-22,011	-25,241	-67,725
Other comprehensive income (loss) before income taxes	-7,543	2,554	-91,680	5,842
Income tax benefit (expense)	566	-729	11,380	-2,090
Other comprehensive income (loss)	-6,977	1,825	-80,300	3,752
Comprehensive income (loss)	$31,308	$86,689	$94,355	$209,435

Consolidated_Statements_of_Sha

Consolidated Statements of Shareholders' Equity (Unaudited) (USD $)	Total	Common shares [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
In Thousands, unless otherwise specified
Balances at Dec. 31, 2011		$355	$313,730	$146,635	$1,230,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common share options		1	2,554
Issuance (cancelation) of common shares			-176
Settlement of equity awards		2	-1,128
Repurchase of common shares		-30	-109,603		0
Amortization of share-based compensation			5,802
Income tax benefit from share-based compensation			367
Other comprehensive income (loss)	3,752			3,752
Net income (loss)	205,683				205,683
Common share dividends	-8,137				-8,137
Balances at Sep. 30, 2012	1,789,946	328	211,546	150,387	1,427,685
Balances at Dec. 31, 2012	1,894,534	327	209,897	137,690	1,546,620
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common share options		4	14,458
Issuance (cancelation) of common shares			-791
Settlement of equity awards		2	-1,270
Repurchase of common shares		-54	-229,878		-72,833
Amortization of share-based compensation			6,661
Income tax benefit from share-based compensation			923
Other comprehensive income (loss)	-80,300			-80,300
Net income (loss)	174,655				174,655
Common share dividends	-7,181				-7,181
Balances at Sep. 30, 2013	$1,698,930	$279	$0	$57,390	$1,641,261

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating Activities:
Net income (loss)	$174,655	$205,683
Adjustments to reconcile net income to cash provided by (used in) operations:
Depreciation and amortization	6,533	4,555
Net realized (gains) losses on investments	-24,698	-70,299
Net impairment losses on investments	2,002	2,882
Net foreign currency exchange losses (gains)	-592	763
Amortization of share-based compensation	9,955	6,805
Deferred income tax expense (benefit)	8,167	3,853
Net fixed maturity trading securities activities	6,993	9,877
Changes in assets and liabilities:
Accrued investment income	557	5,761
Reinsurance premiums receivable	-5,672	8,577
Funds held by ceding companies	-4,622	-18,790
Deferred acquisition costs	-4,257	-403
Reinsurance deposit assets	-27,486	0
Net unpaid and paid losses and loss adjustment expenses	-193,807	-239,970
Net unearned premiums	13,887	9,224
Commissions payable	10,217	4,713
Other assets and liabilities	14,070	47,800
Net cash provided by (used in) operating activities	-14,098	-18,969
Proceeds from the sales of:
Fixed maturity available-for-sale securities	203,571	558,848
Short-term investments	11,857	36,581
Proceeds from maturities or paydowns of:
Fixed maturity available-for-sale securities	155,246	213,503
Short-term investments	209,240	663,011
Acquisitions of:
Fixed maturity available-for-sale securities	-291,006	-202,729
Short-term investments	-121,306	-266,723
Acquisitions of furniture, equipment and other assets	-6,188	0
Net cash provided by (used in) investing activities	161,414	1,002,491
Financing Activities:
Dividends paid to common shareholders	-7,181	-8,137
Repurchase of common shares	-302,765	-109,633
Proceeds from share-based compensation, including income tax benefits	15,385	2,554
Net cash provided by (used in) financing activities	-294,561	-115,216
Effect of foreign currency exchange rate changes on cash and cash equivalents	-7,745	1,863
Net increase (decrease) in cash and cash equivalents	-154,990	870,169
Cash and cash equivalents at beginning of period	1,720,395	792,510
Cash and cash equivalents at end of period	1,565,405	1,662,679
Supplemental disclosures of cash flow information:
Income taxes paid, net of refunds	15,293	14,508
Interest paid	$9,375	$9,375

Basis_of_Presentation_and_Sign

Basis of Presentation and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Basis of Presentation and Significant Accounting Policies [Abstract]
Basis of presentation and significant accounting policies	1.        Basis of Presentation and Significant Accounting Policies
	Basis of Presentation and Consolidation
	Platinum Underwriters Holdings, Ltd. (“Platinum Holdings”) is a holding company domiciled in Bermuda. Through our reinsurance subsidiaries, we provide property and marine, casualty and finite risk reinsurance coverages to a diverse clientele of insurers and select reinsurers on a worldwide basis.
	Platinum Holdings and its consolidated subsidiaries (collectively, the “Company”) include Platinum Holdings, Platinum Underwriters Bermuda, Ltd. (“Platinum Bermuda”), Platinum Underwriters Reinsurance, Inc. (“Platinum US”), Platinum Regency Holdings (“Platinum Regency”), Platinum Underwriters Finance, Inc. (“Platinum Finance”) and Platinum Administrative Services, Inc. The terms “we,” “us,” and “our” refer to the Company, unless the context otherwise indicates.
	We operate through two licensed reinsurance subsidiaries, Platinum Bermuda, a Bermuda reinsurance company, and Platinum US, a U.S. reinsurance company. Platinum Regency is an intermediate holding company based in Ireland and a wholly owned subsidiary of Platinum Holdings. Platinum Finance is an intermediate holding company based in the U.S. and a wholly owned subsidiary of Platinum Regency. Platinum Bermuda is a wholly owned subsidiary of Platinum Holdings and Platinum US is a wholly owned subsidiary of Platinum Finance. Platinum Administrative Services, Inc. is a wholly owned subsidiary of Platinum Finance that provides administrative support services to the Company.
	The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information. Accordingly, they do not include all the information and footnotes required by U.S. GAAP for complete financial statements. All material inter-company transactions and accounts have been eliminated in preparing these consolidated financial statements. The consolidated financial statements as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 are unaudited and include all adjustments consisting of normal recurring items that management considers necessary for a fair presentation under U.S. GAAP. These consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2012.
	The preparation of financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ materially from these estimates. The major estimates used in the preparation of the Company's consolidated financial statements, and therefore considered to be critical accounting estimates, include, but are not limited to, premiums written and earned, unpaid losses and loss adjustment expenses (“LAE”), valuation of investments and income taxes. In addition, estimates are used in our risk transfer analysis for assumed and ceded reinsurance transactions. Results of changes in estimates are reflected in results of operations in the period in which the change is made. The results of operations for any interim period are not necessarily indicative of results for the full year.
	Recently Issued Accounting Standards
	New Accounting Standards Adopted in 2013
	In February 2013, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (“ASU 2013-02”). ASU 2013-02 supersedes and replaces the presentation requirements for reclassifications out of accumulated other comprehensive income in ASU 2011-12 “Comprehensive Income: Deferral of the Effective Date for Amendments to the Presentation of Reclassification of Items Out of Accumulated Other Comprehensive Income in Accounting Standards Update No. 2011-05” and ASU 2011-05 “Presentation of Comprehensive Income” and requires additional information about reclassifications out of accumulated other comprehensive income. None of the other requirements of the previous ASUs are affected by ASU 2013-02. ASU 2013-02 is effective on a prospective basis for interim and annual periods beginning after December 15, 2012. We adopted the guidance as of January 1, 2013 with additional disclosures reflected in Note 10.

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments [Abstract]
Investments	2.        Investments
	Fixed Maturity Available-for-sale Securities
	Our fixed maturity available-for-sale securities are U.S. dollar denominated securities. The following table sets forth our fixed maturity available-for-sale securities as of September 30, 2013 and December 31, 2012 ($ in thousands):
							Included in Accumulated Other Comprehensive Income
			Amortized Cost				Gross Unrealized Gains				Gross Unrealized Losses				Fair Value			Non-credit portion of OTTI(1)
	September 30, 2013:
	U.S. Government		$	4,579			$	230			$	-			$	4,809		$	-
	Municipal bonds			1,217,511				62,751				5,453				1,274,809			-
	Non-U.S. governments			39,971				541				-				40,512			-
	Corporate bonds			226,835				7,023				3,016				230,842			-
	Commercial mortgage-backed securities			83,270				5,126				292				88,104			-
	Residential mortgage-backed securities			178,662				1,500				1,367				178,795			502
	Asset-backed securities			16,257				1,609				357				17,509			286
	Total fixed maturity available-for-sale securities		$	1,767,085			$	78,780			$	10,485			$	1,835,380		$	788
	December 31, 2012:
	U.S. Government		$	4,632			$	312			$	-			$	4,944		$	-
	Municipal bonds			1,080,273				129,735				74				1,209,934			-
	Non-U.S. governments			49,978				999				-				50,977			-
	Corporate bonds			279,981				21,109				182				300,908			-
	Commercial mortgage-backed securities			127,148				8,807				429				135,526			264
	Residential mortgage-backed securities			222,331				2,584				3,293				221,622			2,083
	Asset-backed securities			17,206				1,426				858				17,774			858
	Total fixed maturity available-for-sale securities		$	1,781,549			$	164,972			$	4,836			$	1,941,685		$	3,205
	(1)        The non-credit portion of other than temporary impairments ("OTTI") represents the amount of unrealized losses on impaired securities that were not recorded in the consolidated statements of operations as of the reporting date. These unrealized losses are included in gross unrealized losses as of September 30, 2013 and December 31, 2012.
	Fixed Maturity Trading Securities
	Our fixed maturity trading securities are non-U.S. dollar denominated securities that, along with our non-U.S. dollar short-term trading investments and non-U.S. dollar cash and cash equivalents, are generally held for the purposes of hedging our net non-U.S. dollar denominated reinsurance liabilities.
	The following table sets forth the fair value of our fixed maturity trading securities as of September 30, 2013 and December 31, 2012 ($ in thousands):
			30-Sep-13				December 31, 2012
	Non-U.S. governments		$	102,604			$	112,813
	Total fixed maturity trading securities		$	102,604			$	112,813
	Maturities
	The following table sets forth the amortized cost and fair value of our fixed maturity available-for-sale and trading securities by stated maturity as of September 30, 2013 ($ in thousands):
			Amortized Cost				Fair Value
	Due in one year or less		$	41,124			$	41,612
	Due from one to five years			475,473				495,931
	Due from five to ten years			658,273				681,902
	Due in ten or more years			410,416				434,131
	Mortgage-backed and asset-backed securities			278,189				284,408
	Total		$	1,863,475			$	1,937,984
	The actual maturities of our fixed maturity available-for-sale and trading securities could differ from stated maturities due to call or prepayment provisions.
	Short-term Investments
	The following table sets forth the fair value of our short-term investments as of September 30, 2013 and December 31, 2012 ($ in thousands):
			30-Sep-13				December 31, 2012
	Available-for-sale:
	U.S. Government		$	-			$	49,186
	Trading:
	Non-U.S. governments			73,635				123,615
	Total short-term investments		$	73,635			$	172,801
	The fair value adjustments on short-term investments recognized as trading under the fair value option contributed no realized gains or losses on investments for the three and nine months ended September 30, 2013 and 2012.
	For the nine months ended September 30, 2013, we had purchases of $121.3 million, proceeds from maturities of $160.0 million and proceeds from sales of $11.9 million from non-U.S. dollar denominated short-term investments accounted for as trading in accordance with the fair value option that were included in investing activities on the statements of cash flows.  For the nine months ended September 30, 2012, we had purchases of $204.3 million, proceeds from maturities of $242.0 million and proceeds from sales of $36.6 million from non-U.S. dollar denominated short-term investments accounted for as trading in accordance with the fair value option that were included in investing activities on the statements of cash flows.
	Other-Than-Temporary Impairments
	The following table sets forth the net impairment losses on investments for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
	Commercial mortgage-backed securities		$	-			$	-			$	-			$	30
	Non-agency residential mortgage-backed securities			28				693				1,439				2,839
	Sub-prime asset-backed securities			37				6				563				13
	Net impairment losses on investments		$	65			$	699			$	2,002			$	2,882
	We analyze the creditworthiness of our available-for-sale securities by reviewing various performance metrics of the issuer. We determined that none of our government bonds, municipal bonds or corporate bonds were other-than-temporarily impaired for the three and nine months ended September 30, 2013 and 2012.
	We analyze our commercial mortgage-backed securities (“CMBS”) on a periodic basis using default loss models based on the performance of the underlying loans. Performance metrics include delinquencies, defaults, foreclosures, debt-service-coverage ratios and cumulative losses incurred. The expected losses for a mortgage pool are compared with the current level of credit support, which generally represents the point at which our security would experience losses. We evaluate projected cash flows as well as other factors in order to determine if a credit impairment has occurred. As of September 30, 2013, the single largest unrealized loss within our CMBS portfolio was $0.3 million related to a security with an amortized cost of $4.8 million.
	Residential mortgage-backed securities (“RMBS”) include U.S. Government agency RMBS and non-agency RMBS. Securities with underlying sub-prime mortgages as collateral are included in asset-backed securities (“ABS”). We determined that none of our U.S. Government agency RMBS were other-than-temporarily impaired for the three and nine months ended September 30, 2013 and 2012. We analyze our non-agency RMBS and sub-prime ABS on a periodic basis using default loss models based on the performance of the underlying loans. Performance metrics include delinquencies, defaults, foreclosures, prepayment speeds and cumulative losses incurred. The expected losses for a mortgage pool are compared with the current level of credit support, which generally represents the point at which our security would experience losses. We evaluate projected cash flows as well as other factors in order to determine if a credit impairment has occurred. As of September 30, 2013, the single largest unrealized loss within our RMBS portfolio was $0.6 million related to a non-agency RMBS security with an amortized cost of $4.1 million. As of September 30, 2013, the single largest unrealized loss within our sub-prime ABS portfolio was $0.3 million related to a security with an amortized cost of $0.6 million.
	The following table sets forth a summary of the cumulative credit losses recognized on our fixed maturity available-for-sale securities for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
			Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013				2012				2013				2012
Balance, beginning of period		$	35,762			$	57,874			$	40,219			$	61,841
Credit losses on securities not previously impaired			-				42				-				42
Credit losses on securities previously impaired			65				657				2,002				2,840
Reduction for paydowns and securities sold			(2,956	)			(3,447	)			(9,094	)			(9,168	)
Reduction for increases in cash flows expected to be collected			(195	)			(309	)			(451	)			(738	)
Balance, end of period		$	32,676			$	54,817			$	32,676			$	54,817
As of September 30, 2013, total cumulative credit losses were related to CMBS, non-agency RMBS and sub-prime ABS. The cumulative credit losses we recorded on CMBS of $1.2 million were on two securities issued in 2007.  As of September 30, 2013, 3.4% of the mortgages backing these securities were 90 days or more past due and 1.0% of the mortgages had incurred cumulative losses. For these securities, the expected losses for the underlying mortgages were greater than the remaining credit support of 4.6%.  The cumulative credit losses we recorded on non-agency RMBS and sub-prime ABS of $31.5 million were on seventeen securities issued from 2004 to 2007.  As of September 30, 2013, 16.0% of the mortgages backing these securities were 90 days or more past due and 7.9% of the mortgages had incurred cumulative losses. For these securities, the expected losses for the underlying mortgages were greater than the remaining credit support of 2.9%.
Gross Unrealized Losses
The following table sets forth our gross unrealized losses on securities classified as fixed maturity available-for-sale aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2013 and December 31, 2012 ($ in thousands):
		30-Sep-13								December 31, 2012
		Fair Value				Unrealized Loss				Fair Value				Unrealized Loss
Less than twelve months:
Municipal bonds		$	207,187			$	5,453			$	18,878			$	74
Corporate bonds			85,865				3,016				4,450				41
Commercial mortgage-backed securities			4,463				292				6,758				165
Residential mortgage-backed securities			28,640				162				39				9
Asset-backed securities			13,529				71				64				1
Total		$	339,684			$	8,994			$	30,189			$	290
Twelve months or more:
Municipal bonds		$	-			$	-			$	-			$	-
Corporate bonds			-				-				6,039				141
Commercial mortgage-backed securities			-				-				762				264
Residential mortgage-backed securities			14,572				1,205				17,096				3,284
Asset-backed securities			772				286				799				857
Total		$	15,344			$	1,491			$	24,696			$	4,546
Total unrealized losses:
Municipal bonds		$	207,187			$	5,453			$	18,878			$	74
Corporate bonds			85,865				3,016				10,489				182
Commercial mortgage-backed securities			4,463				292				7,520				429
Residential mortgage-backed securities			43,212				1,367				17,135				3,293
Asset-backed securities			14,301				357				863				858
Total		$	355,028			$	10,485			$	54,885			$	4,836
We believe that the gross unrealized losses in our fixed maturity available-for-sale securities portfolio of $10.5 million represent temporary declines in fair value.  We believe that the unrealized losses are not necessarily predictive of ultimate performance and that the provisions we have made for net impairment losses are adequate.  However, economic conditions may deteriorate more than expected and may adversely affect the expected cash flows of our securities, which in turn may lead to impairment losses being recorded in future periods.  Conversely, economic conditions may improve more than expected and favorably increase the expected cash flows of our impaired securities, which would be earned through net investment income over the remaining life of the security.
Net Investment Income
The following table sets forth our net investment income for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
	Three Months Ended								Nine Months Ended
	September 30,								September 30,
	2013				2012				2013				2012
Fixed maturity securities	$	16,815			$	22,022			$	51,428			$	73,892
Short-term investments and cash and cash equivalents		1,123				1,547				3,346				5,358
Funds held by ceding companies		722				684				2,375				1,938
Subtotal		18,660				24,253				57,149				81,188
Investment expenses		(902	)			(1,044	)			(3,039	)			(3,272	)
Net investment income	$	17,758			$	23,209			$	54,110			$	77,916
Net Realized Gains (Losses) on Investments
The following table sets forth our net realized gains (losses) on investments for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
	Three Months Ended								Nine Months Ended
	September 30,								September 30,
	2013				2012				2013				2012
Gross realized gains on the sale of investments	$	-			$	22,979			$	27,258			$	70,920
Gross realized losses on the sale of investments		-				-				(15	)			(1	)
Net realized gains on the sale of investments		-				22,979				27,243				70,919
Fair value adjustments on trading securities		(306	)			3				(2,545	)			(620	)
Net realized gains (losses) on investments	$	(306	)		$	22,982			$	24,698			$	70,299

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Measurements [Abstract]
Fair value measurements	3.        Fair Value Measurements
	The accounting guidance related to fair value measurements addresses the recognition and disclosure of fair value measurements where those measurements are either required or permitted by the guidance. The fair values of our financial assets and liabilities addressed by this guidance are determined primarily through the use of observable inputs. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability based on market data obtained from external independent sources.  Unobservable inputs reflect management’s assumptions about what market participants’ assumptions would be in pricing the asset or liability based on the best information available.  We classify our financial assets and liabilities in the fair value hierarchy based on the lowest level input that is significant to the fair value measurement. This classification requires judgment in assessing the market and pricing methodologies for a particular security. The fair value hierarchy is comprised of the following three levels:
	Level 1:        Valuations are based on unadjusted quoted prices in active markets for identical financial assets or liabilities;
	Level 2:        Valuations are based on prices obtained from independent pricing vendors, index providers or broker-dealers using observable inputs for financial assets and liabilities; and
	Level 3:        Valuations are based on unobservable inputs for assets and liabilities where there is little or no market activity. Unadjusted third party pricing sources or management’s assumptions and internal valuation models may be used to determine the fair value of financial assets or liabilities.
	Level 1, 2 and 3 Financial Assets Carried at Fair Value
	Fixed maturity securities, short-term investments and our reinsurance deposit assets are generally valued using the market approach. The fair values of our fixed maturity securities and short-term investments are based on prices primarily obtained from pricing vendors, index providers, or broker-dealers using observable inputs. We validate the prices we obtain from third party pricing sources by performing price comparisons against multiple pricing sources, if available, periodically back-testing of sales to the previously reported fair value, performing an in-depth review of specific securities when evaluating stale prices and large price movements, as well as performing other validation procedures. We also continuously monitor market data that relates to our investment portfolio and review pricing documentation that describes the methodologies used by various pricing vendors. If we determine that a price appears unreasonable, we investigate and assess whether the price should be adjusted. Our fixed maturity securities, short-term investments and reinsurance deposit assets are classified in the fair value hierarchy as follows:
	U.S. Government
	Level 1 - The fair values of U.S. Government securities were based on quoted prices in active markets for identical assets.
	Municipal bonds
	Level 2 - The fair values of municipal bonds were determined based on observable inputs that may include the spread above the risk-free yield curve, reported trades, broker-dealer quotes, benchmark securities, bids, credit risks and economic indicators.
	Non-U.S. governments
	Level 1 or 2 - The fair values of non-U.S. government securities were determined based on quoted prices in active markets for identical assets or observable inputs that may include the spread above the risk-free yield curve, reported trades and broker-dealer quotes. Our non-U.S. government bond portfolio consisted of securities issued primarily by governments, provinces, agencies and supranationals.
	Corporate bonds
	Level 2 - The fair values of corporate bonds were determined based on observable inputs that may include the spread above the risk-free yield curve, reported trades, broker-dealer quotes, benchmark securities, bids, credit risks and industry and economic indicators.
	Commercial mortgage-backed securities
	Level 2 or 3 - The fair values of CMBS classified as Level 2 were determined based on observable inputs that may include the spread above the risk-free yield curve, reported trades, broker-dealer quotes, bids, security cash flows and structures, delinquencies, loss severities and default rates. CMBS classified as Level 3 used unobservable inputs that may include the probability of default and loss severity in the event of default.
	Residential mortgage-backed securities
	Level 2 or 3 - Our RMBS portfolio was comprised of securities issued by U.S. Government agencies and by non-agency institutions. The fair values of RMBS classified as Level 2 were determined based on observable inputs that may include the spread above the risk-free yield curve, reported trades, broker-dealer quotes, bids, loan level information, security cash flows and structures, prepayment speeds, delinquencies, loss severities and default rates. Non-agency RMBS classified as Level 3 used unobservable inputs that may include the probability of default, loss severity in the event of default and prepayment speeds.
	Asset-backed securities
	Level 2 or 3 - The fair values of ABS classified as Level 2 were determined based on observable inputs that may include the spread above the risk-free yield curve, reported trades, broker-dealer quotes, bids, security cash flows and structures, type of collateral, prepayment speeds, delinquencies, loss severities and default rates. Sub-prime ABS classified as Level 3 used unobservable inputs that may include the probability of default, loss severity in the event of default and prepayment speeds.
	Short-term investments
	Level 2 - The fair values of short-term investments were determined based on observable inputs that may include the spread above the risk-free yield curve, reported trades and broker-dealer quotes.
	Reinsurance deposit assets
	Level 3 - The fair values of our reinsurance deposit assets were determined by management primarily using unobservable inputs through the application of our own assumptions and internal valuation model.
	The following table presents the fair value hierarchy for those financial assets and liabilities measured at fair value on a recurring basis by the Company as of September 30, 2013 and December 31, 2012 ($ in thousands):
					Fair Value Measurement Using:
		Total			Level 1			Level 2			Level 3
	September 30, 2013:
	Investments:
	U.S. Government	$	4,809		$	4,809		$	-		$	-
	Municipal bonds		1,274,809			-			1,274,809			-
	Non-U.S. governments		143,116			54,437			88,679			-
	Corporate bonds		230,842			-			230,842			-
	Commercial mortgage-backed securities		88,104			-			88,104			-
	Residential mortgage-backed securities		178,795			-			178,280			515
	Asset-backed securities		17,509			-			14,949			2,560
	Short-term investments		73,635			-			73,635			-
	Total investments		2,011,619			59,246			1,949,298			3,075
	Reinsurance deposit assets		78,179			-			-			78,179
	Total	$	2,089,798		$	59,246		$	1,949,298		$	81,254
	December 31, 2012:
	Investments:
	U.S. Government	$	4,944		$	4,944		$	-		$	-
	Municipal bonds		1,209,934			-			1,209,934			-
	Non-U.S. governments		163,790			56,422			107,368			-
	Corporate bonds		300,908			-			300,908			-
	Commercial mortgage-backed securities		135,526			-			135,002			524
	Residential mortgage-backed securities		221,622			-			216,248			5,374
	Asset-backed securities		17,774			-			16,738			1,036
	Short-term investments		172,801			-			172,801			-
	Total investments		2,227,299			61,366			2,158,999			6,934
	Reinsurance deposit asset		50,693			-			-			50,693
	Total	$	2,277,992		$	61,366		$	2,158,999		$	57,627
	There were no transfers between Levels 1 and 2 during the three and nine months ended September 30, 2013 and 2012. Transfers of assets into or out of Level 3 are recorded at their fair values as of the end of each reporting period, consistent with the date of the determination of fair value. The transfers into and out of Level 3 were based on the level of evidence available to corroborate significant observable inputs with market observable information.
	Changes in Level 3 Financial Assets
	The following table reconciles the beginning and ending balance for our Level 3 financial assets measured at fair value on a recurring basis for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended September 30, 2013
		Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
	Balance, beginning of period	$	-		$	4,520		$	1,257		$	76,948	$	82,725
	Sales, maturities and paydowns		-			(269	)		-			-		(269	)
	Total increase (decrease) in fair value included in earnings		-			-			-			1,231		1,231
	Total net unrealized gains (losses) included in other comprehensive income (loss)		-			329			(75	)		-		254
	Transfers into Level 3		-			-			1,378			-		1,378
Transfers out of Level 3		-			(4,065	)		-			-		(4,065	)
Balance, end of period	$	-		$	515		$	2,560		$	78,179	$	81,254
Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	1,231	$	1,231
	Three Months Ended September 30, 2012
	Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
Balance, beginning of period	$	-		$	7,461		$	1,566		$	-	$	9,027
Sales, maturities and paydowns		-			(935	)		-			-		(935	)
Total net unrealized gains (losses) included in other comprehensive income (loss)		-			1,789			(30	)		-		1,759
Transfers into Level 3		-			3,807			4,932			-		8,739
Transfers out of Level 3		-			(3,915	)		(399	)		-		(4,314	)
Balance, end of period	$	-		$	8,207		$	6,069		$	-	$	14,276
Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	-	$	-
	Nine Months Ended September 30, 2013
	Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
Balance, beginning of period	$	524		$	5,374		$	1,036		$	50,693	$	57,627
Purchases		-			-			-			25,000		25,000
Sales, maturities and paydowns		-			(435	)		(29	)		-		(464	)
Total increase (decrease) in fair value included in earnings		-			-			-			2,486		2,486
Total net unrealized gains (losses) included in other comprehensive income (loss)		487			750			(46	)		-		1,191
Transfers into Level 3		-			4,049			3,984			-		8,033
Transfers out of Level 3		(1,011	)		(9,223	)		(2,385	)		-		(12,619	)
Balance, end of period	$	-		$	515		$	2,560		$	78,179	$	81,254
Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	2,486	$	2,486
	Nine Months Ended September 30, 2012
	Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
Balance, beginning of period	$	-		$	8,146		$	1,867		$	-	$	10,013
Sales, maturities and paydowns		-			(1,669	)		-			-		(1,669	)
Total net unrealized gains (losses) included in other comprehensive income (loss)		-			1,839			(331	)		-		1,508
Transfers into Level 3		-			6,060			4,932			-		10,992
Transfers out of Level 3		-			(6,169	)		(399	)		-		(6,568	)
Balance, end of period	$	-		$	8,207		$	6,069		$	-	$	14,276
Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	-	$	-
Quantitative Information of Level 3 Fair Value Measurements
The fair value measurements of our CMBS, non-agency RMBS and sub-prime ABS classified as Level 3 were based on unadjusted third party pricing sources.
Our reinsurance deposit assets represent retrocessional aggregate excess of loss reinsurance agreements we purchased for consideration of $75.0 million.  We elected to record our reinsurance deposit assets under the fair value option as the terms and conditions of these contracts have unique variable investment performance factors.  The terms of these agreements provide for a book yield ranging from a minimum of 3.0% to a maximum of 6.5% accumulating over the estimated contract periods.
The fair value measurements of our reinsurance deposit assets used significant unobservable inputs through the application of our own assumptions and internal valuation model and were classified as Level 3. The most significant unobservable inputs used in our internal valuation model are the estimated contract period remaining, credit spread above the risk-free rate and net losses and LAE ceded. The credit spread above the risk-free rate is determined by reviewing the credit spreads of fixed income securities through observable market data, as well as considering illiquidity and the structure of these contracts.  The fair value of the reinsurance deposit assets may increase or decrease due to changes in the estimated contract period remaining, the credit spread and net losses and LAE ceded. Generally, a decrease in the credit spread or a decrease in net losses and LAE ceded would result in an increase in the fair value of the reinsurance deposit assets. Conversely, an increase in the credit spread or an increase in net losses and LAE ceded would result in a decrease in the fair value of the reinsurance deposit assets.
The following table sets forth the weighted average of the significant unobservable quantitative information used for the fair value measurement of our reinsurance deposit assets as of September 30, 2013 and December 31, 2012:
	30-Sep-13			31-Dec-12
Estimated contract period remaining		1,282 days			1,350 days
Credit spread above the risk-free rate		1.84	%		2.47	%
Net losses and LAE ceded inception-to-date	$	-		$	-
Other Financial Assets and Liabilities Not Carried at Fair Value
Accounting guidance requires note disclosure of the fair value of other financial assets and liabilities not carried at fair value, excluding balances related to insurance contracts.
The debt obligations on our consolidated balance sheets were recorded at cost with a carrying value of $250.0 million at September 30, 2013 and December 31, 2012, and had a fair value of $273.0 million and $278.5 million at September 30, 2013 and December 31, 2012, respectively. The fair value measurements were based on observable inputs and therefore would be considered to be Level 2.
Our remaining financial assets and liabilities were generally carried at cost or amortized cost, which approximates fair value, at September 30, 2013 and December 31, 2012. The fair value measurements were based on observable inputs and therefore would be considered to be Level 1 or Level 2.

Credit_Facilities

Credit Facilities	9 Months Ended
	Sep. 30, 2013
Credit Facilities [Abstract]
Credit facilities	4.        Credit Facilities
	As of September 30, 2013, we had a $300.0 million credit facility with various financial institutions (the "Syndicated Credit Facility") available for revolving borrowings and letters of credit (“LOC”). In addition, our reinsurance subsidiaries had other LOC facilities available for the issuance of LOC to collateralize their reinsurance obligations.  We had no revolving borrowings under the Syndicated Credit Facility during the nine months ended September 30, 2013 and the year ended December 31, 2012.
	The following table summarizes the outstanding LOC and the cash and cash equivalents held in trust to collateralize LOC issued as of September 30, 2013 ($ in thousands):
		Letters of Credit				Collateral
		Committed Capacity		Issued		Cash and Cash Equivalents
	Syndicated Credit Facility:
	Secured	$	200,000	$	80,405	$	93,356
	Unsecured		100,000		-		-
	Total Syndicated Credit Facility		300,000		80,405		93,356
	Other LOC Facilities		115,405		44,068		67,317
	Total	$	415,405	$	124,473	$	160,673
	As of September 30, 2013, we were in compliance with covenants under our credit facilities.
	On July 2, 2013, Platinum Bermuda increased the amount of an uncommitted LOC facility by $50.0 million. Our reinsurance subsidiaries have a total uncommitted LOC capacity of $259.6 million available. The Company also has the ability to increase the syndicated and other LOC facilities by up to $175.0 million, subject to agreement with the lenders.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Taxes [Abstract]
Income taxes	5.        Income Taxes
	We provide for income tax expense or benefit based upon pre-tax income reported in the consolidated financial statements and the provisions of currently enacted tax laws. Platinum Holdings and Platinum Bermuda are incorporated under the laws of Bermuda and are subject to Bermuda law with respect to taxation. Under current Bermuda law, Platinum Holdings and Platinum Bermuda are not taxed on any Bermuda income or capital gains and they have received an assurance from the Bermuda Minister of Finance that if any legislation is enacted in Bermuda that would impose tax computed on profits or income, or computed on any capital asset, gain or appreciation, or any tax in the nature of estate duty or inheritance tax, then the imposition of any such tax will not be applicable to Platinum Holdings or Platinum Bermuda or any of their respective operations, shares, debentures or other obligations until March 31, 2035. Platinum Holdings has subsidiaries based in the United States and Ireland that are subject to the tax laws thereof.
	The U.S. Internal Revenue Service completed its examination of the 2003 federal income tax return of our U.S.-based subsidiaries and in April 2013 the Company received a refund of $6.0 million, including accrued interest of $1.3 million, related to this return. The federal income tax returns of our U.S.-based subsidiaries that remain open to examination are for calendar years 2010 and later.

Share_Repurchases

Share Repurchases	9 Months Ended
	Sep. 30, 2013
Share Repurchases [Abstract]
Share repurchases	6.        Share Repurchases
	Our Board of Directors has authorized the repurchase of our common shares through a share repurchase program. Since the program was established, our Board of Directors has approved increases in the repurchase program from time to time, most recently on July 24, 2013, to result in authority as of such date to repurchase up to a total of $250.0 million of our common shares.
	In accordance with the share repurchase program, during the three months ended September 30, 2013 we repurchased 1,353,682 of our common shares in the open market for an aggregate cost of $78.5 million at a weighted average cost including commissions of $58.01 per share. During the nine months ended September 30, 2013 we repurchased 5,351,343 of our common shares in the open market for an aggregate cost of $302.8 million at a weighted average cost including commissions of $56.58 per share. The shares we repurchased were canceled.
	As of September 30, 2013, we had $171.5 million remaining under the share repurchase program.

Statutory_Regulations_and_Divi

Statutory Regulations and Dividend Restictions	9 Months Ended
	Sep. 30, 2013
Statutory Regulations And Dividend Restrictions [Abstract]
Statutory regulations and dividend restrictions	7.        Statutory Regulations and Dividend Restrictions
	Platinum Holdings and its subsidiaries are subject to certain legal and regulatory restrictions in their respective jurisdictions of domicile. The legal restrictions generally include the requirement to maintain positive net assets and to be able to pay liabilities as they become due. Regulatory restrictions on dividends are described below.
	Dividend Restrictions on Platinum Holdings
	There are no regulatory restrictions on retained earnings available for the payment of dividends by Platinum Holdings to its shareholders.
	Dividend Restrictions on Subsidiaries
	The laws and regulations of Bermuda and the United States include certain restrictions on the amount of statutory capital and surplus that are available for the payment of dividends by Platinum Bermuda and Platinum US to their respective parent companies, Platinum Holdings and Platinum Finance, without the prior approval of the relevant regulatory authorities. The following table summarizes the dividend capacity of our reinsurance subsidiaries for 2013 ($ in thousands):
		2013		For the Nine Months Ended September 30, 2013		30-Sep-13
		Dividend Capacity		Paid		Remaining
	Platinum Bermuda	$	318,343	$	262,500	$	55,843
	Platinum US		30,779		-		30,779
	Total	$	349,122	$	262,500	$	86,622
	Subsequent to September 30, 2013, Platinum Bermuda declared and paid a dividend of $55.8 million to Platinum Holdings.
	There are no regulatory restrictions on retained earnings available for the payment of dividends by Platinum Finance to Platinum Regency or by Platinum Regency to Platinum Holdings.

Operating_Segment_Information

Operating Segment Information	9 Months Ended
	Sep. 30, 2013
Operating Segment Information [Abstract]
Operating segment information	8.        Operating Segment Information
	We have organized our worldwide reinsurance business into three operating segments: Property and Marine, Casualty and Finite Risk. In managing our operating segments, we use measures such as underwriting income or loss and related underwriting ratios to allow for a more complete understanding of the underlying business. Such measures are considered to be non-GAAP. These non-GAAP measures may be defined or calculated differently by other companies. These measures are used to monitor our results and should not be viewed as a substitute for those determined in accordance with U.S. GAAP.
	Underwriting income or loss measures the performance of the Company’s underwriting function and consists of net premiums earned less net losses and LAE and net underwriting expenses. Net underwriting expenses include net acquisition expenses and operating costs related to underwriting. Underwriting income or loss excludes revenues and expenses related to net investment income, net realized gains or losses on investments, net impairment losses on investments, corporate expenses not allocated to underwriting operations, interest expense, net foreign currency exchange gains or losses and other income and expense.
	Underwriting ratios are calculated for net losses and LAE, net acquisition expense and net underwriting expense. The ratios are calculated by dividing the related expense by net premiums earned. The combined ratio is the sum of the net losses and LAE, net acquisition expense and net underwriting expense ratios. The Company believes that underwriting income or loss and ratios highlight the profitability of our reinsurance operations.
	The following table summarizes underwriting activity and ratios for the three operating segments, together with a reconciliation of segment underwriting income (loss) to the U.S. GAAP measure of income before income taxes for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended September 30, 2013
		Property and Marine			Casualty			Finite Risk			Total
	Net premiums written	$	59,169		$	69,992		$	8,737		$	137,898
	Net premiums earned		55,127			72,543			7,690			135,360
	Net losses and loss adjustment expenses		28,339			10,242			5,561			44,142
	Net acquisition expenses		9,699			19,067			1,909			30,675
	Other underwriting expenses		7,747			5,727			342			13,816
	Segment underwriting income (loss)	$	9,342		$	37,507		$	(122	)		46,727
	Net investment income											17,758
	Net realized gains (losses) on investments											(306	)
	Net impairment losses on investments											(65	)
	Other income (expense)											1,426
	Corporate expenses not allocated to segments											(6,856	)
	Net foreign currency exchange (losses) gains											(487	)
	Interest expense											(4,782	)
	Income before income taxes										$	53,415
	Underwriting ratios:
	Net loss and loss adjustment expense		51.4	%		14.1	%		72.3	%		32.6	%
	Net acquisition expense		17.6	%		26.3	%		24.8	%		22.7	%
	Other underwriting expense		14.1	%		7.9	%		4.4	%		10.2	%
	Combined		83.1	%		48.3	%		101.5	%		65.5	%
		Three Months Ended September 30, 2012
		Property and Marine			Casualty			Finite Risk			Total
	Net premiums written	$	64,876		$	72,358		$	8,745		$	145,979
	Net premiums earned		61,900			70,326			6,362			138,588
	Net losses and loss adjustment expenses		26,790			14,358			3,969			45,117
	Net acquisition expenses		7,078			16,710			2,380			26,168
	Other underwriting expenses		7,661			5,662			289			13,612
	Segment underwriting income (loss)	$	20,371		$	33,596		$	(276	)		53,691
	Net investment income											23,209
	Net realized gains (losses) on investments											22,982
	Net impairment losses on investments											(699	)
	Other income (expense)											(96	)
	Corporate expenses not allocated to segments											(6,354	)
	Net foreign currency exchange (losses) gains											(541	)
	Interest expense											(4,775	)
	Income before income taxes										$	87,417
	Underwriting ratios:
	Net loss and loss adjustment expense		43.3	%		20.4	%		62.4	%		32.6	%
	Net acquisition expense		11.4	%		23.8	%		37.4	%		18.9	%
	Other underwriting expense		12.4	%		8.1	%		4.5	%		9.8	%
	Combined		67.1	%		52.3	%		104.3	%		61.3	%
		Nine Months Ended September 30, 2013
		Property and Marine			Casualty			Finite Risk			Total
	Net premiums written	$	175,946		$	220,547		$	22,540		$	419,033
	Net premiums earned		165,811			218,967			20,368			405,146
	Net losses and loss adjustment expenses		35,426			75,243			10,138			120,807
	Net acquisition expenses		27,624			53,384			10,199			91,207
	Other underwriting expenses		22,493			17,120			1,002			40,615
	Segment underwriting income (loss)	$	80,268		$	73,220		$	(971	)		152,517
	Net investment income											54,110
	Net realized gains on investments											24,698
	Net impairment losses on investments											(2,002	)
	Other income (expense)											2,503
	Corporate expenses not allocated to segments											(19,080	)
	Net foreign currency exchange (losses) gains											592
	Interest expense											(14,341	)
	Income before income taxes										$	198,997
	Underwriting ratios:
Net loss and loss adjustment expense		21.4	%		34.4	%		49.8	%		29.8	%
Net acquisition expense		16.7	%		24.4	%		50.1	%		22.5	%
Other underwriting expense		13.6	%		7.8	%		4.9	%		10	%
Combined		51.7	%		66.6	%		104.8	%		62.3	%
	Nine Months Ended September 30, 2012
	Property and Marine			Casualty			Finite Risk			Total
Net premiums written	$	194,724		$	219,436		$	16,939		$	431,099
Net premiums earned		186,066			221,838			13,971			421,875
Net losses and loss adjustment expenses		85,380			101,245			4,805			191,430
Net acquisition expenses		25,034			52,572			9,419			87,025
Other underwriting expenses		21,950			16,323			747			39,020
Segment underwriting income (loss)	$	53,702		$	51,698		$	(1,000	)		104,400
Net investment income											77,916
Net realized gains on investments											70,299
Net impairment losses on investments											(2,882	)
Other income (expense)											(766	)
Corporate expenses not allocated to segments											(17,625	)
Net foreign currency exchange (losses) gains											(763	)
Interest expense											(14,321	)
Income before income taxes										$	216,258
Underwriting ratios:
Net loss and loss adjustment expense		45.9	%		45.6	%		34.4	%		45.4	%
Net acquisition expense		13.5	%		23.7	%		67.4	%		20.6	%
Other underwriting expense		11.8	%		7.4	%		5.3	%		9.2	%
Combined		71.2	%		76.7	%		107.1	%		75.2	%

Earnings_Loss_Per_Common_Share

Earnings (Loss) Per Common Share	9 Months Ended
	Sep. 30, 2013
Earnings (Loss) Per Common Share [Abstract]
Earnings (loss) per common share	9.        Earnings Per Common Share
	The following is a reconciliation of basic and diluted earnings per common share for the three and nine months ended September 30, 2013 and 2012 ($ and amounts in thousands, except per share data):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	Earnings
	Basic and Diluted
	Net income attributable to common shareholders	$	38,285		$	84,864		$	174,655		$	205,683
	Portion allocated to participating common shareholders (1)		(26	)		(234	)		(301	)		(740	)
	Net income allocated to common shareholders	$	38,259		$	84,630		$	174,354		$	204,943
	Common Shares
	Basic
	Weighted average common shares outstanding		28,655			32,996			30,519			34,063
	Diluted
	Weighted average common shares outstanding		28,655			32,996			30,519			34,063
	Effect of dilutive securities:
	Common share options		131			179			173			154
	Restricted share units		279			97			257			69
	Adjusted weighted average common shares outstanding		29,065			33,272			30,949			34,286
	Earnings Per Common Share
	Basic earnings per common share	$	1.34		$	2.56		$	5.71		$	6.02
	Diluted earnings per common share	$	1.32		$	2.54		$	5.63		$	5.98
	(1)        Represents earnings attributable to holders of unvested restricted shares issued under the Company's share incentive plans that are considered to be participating securities. In July 2013, the remaining outstanding restricted shares vested and therefore there were no unvested restricted shares as of September 30, 2013.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income [Abstract]
Accumulated other comprehensive income (loss)	10.         Accumulated Other Comprehensive Income
	Accumulated other comprehensive income in the consolidated balance sheets relates to unrealized gains and losses on available-for-sale securities, net of deferred taxes.
	The following table reconciles the beginning and ending balances for accumulated other comprehensive income for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended September 30, 2013
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	75,838		$	(11,471	)	$	64,367
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		14			-			14
	Change in net unrealized gains and losses on all other securities		(7,622	)		566			(7,056	)
	Total change in net unrealized gains and losses		(7,608	)		566			(7,042	)
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		-			-			-
	Net impairment losses on investments		65			-			65
	Total reclassifications to net income		65			-			65
	Other comprehensive income (loss)		(7,543	)		566			(6,977	)
	Balance, end of period	$	68,295		$	(10,905	)	$	57,390
		Three Months Ended September 30, 2012
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	172,149		$	(23,587	)	$	148,562
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		354			19			373
	Change in net unrealized gains and losses on all other securities		24,211			(3,181	)		21,030
	Total change in net unrealized gains and losses		24,565			(3,162	)		21,403
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		(22,710	)		2,466			(20,244	)
	Net impairment losses on investments		699			(33	)		666
	Total reclassifications to net income		(22,011	)		2,433			(19,578	)
	Other comprehensive income (loss)		2,554			(729	)		1,825
	Balance, end of period	$	174,703		$	(24,316	)	$	150,387
		Nine Months Ended September 30, 2013
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	159,975		$	(22,285	)	$	137,690
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		(600	)		11			(589	)
	Change in net unrealized gains and losses on all other securities		(65,839	)		7,727			(58,112	)
	Total change in net unrealized gains and losses		(66,439	)		7,738			(58,701	)
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		(27,243	)		3,675			(23,568	)
	Net impairment losses on investments		2,002			(33	)		1,969
	Total reclassifications to net income		(25,241	)		3,642			(21,599	)
	Other comprehensive income (loss)		(91,680	)		11,380			(80,300	)
	Balance, end of period	$	68,295		$	(10,905	)	$	57,390
		Nine Months Ended September 30, 2012
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	168,861		$	(22,226	)	$	146,635
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		263			79			342
	Change in net unrealized gains and losses on all other securities		73,304			(6,124	)		67,180
	Total change in net unrealized gains and losses		73,567			(6,045	)		67,522
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		(70,607	)		4,220			(66,387	)
	Net impairment losses on investments		2,882			(265	)		2,617
	Total reclassifications to net income		(67,725	)		3,955			(63,770	)
	Other comprehensive income (loss)		5,842			(2,090	)		3,752
	Balance, end of period	$	174,703		$	(24,316	)	$	150,387
	The following table sets forth the amounts reclassified out of accumulated other comprehensive income and the location of those amounts in the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		September 30,						September 30,
		2013			2012			2013			2012
	Revenue:
	Net realized gains on investments	$	-		$	22,710		$	27,243		$	70,607
	Net impairment losses on investments		(65	)		(699	)		(2,002	)		(2,882	)
	Income tax expense	$	-		$	2,433		$	3,642		$	3,955

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies [Abstract]
Commitments and contingencies	11.        Commitments
	During the quarter ended September 30, 2013, Platinum Holdings and Platinum Bermuda entered into ten-year lease agreements for new office space in Pembroke, Bermuda.  Our contractual obligations for these operating leases are $1.1 million annually beginning August 27, 2013, for a total of $10.8 million for the ten-year lease term.

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information	9 Months Ended
	Sep. 30, 2013
Condensed Consolidating Financial Information [Abstract]
Condensed consolidating financial information	12.        Condensed Consolidating Financial Information
	Platinum Holdings fully and unconditionally guarantees the $250.0 million of debt obligations issued by its 100%-owned subsidiary Platinum Finance.
	The following tables present the condensed consolidating financial information for Platinum Holdings, Platinum Finance and the non-guarantor subsidiaries of Platinum Holdings as of September 30, 2013 and December 31, 2012 and for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
	Condensed Consolidating Balance Sheet
	30-Sep-13
		Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
	ASSETS
	Total investments	$	-		$	126		$	2,011,493		$	-		$	2,011,619
	Investment in subsidiaries		1,667,006			680,845			574,649			(2,922,500	)		-
	Cash and cash equivalents		28,124			148,204			1,389,077			-			1,565,405
	Reinsurance assets		-			-			293,775			-			293,775
	Other assets		12,248			1,808			124,404			-			138,460
	Total assets	$	1,707,378		$	830,983		$	4,393,398		$	(2,922,500	)	$	4,009,259
	LIABILITIES AND SHAREHOLDERS' EQUITY
	Liabilities
	Reinsurance liabilities	$	-		$	-		$	1,963,712		$	-		$	1,963,712
	Debt obligations		-			250,000			-			-			250,000
	Other liabilities		8,448			6,334			81,835			-			96,617
	Total liabilities	$	8,448		$	256,334		$	2,045,547		$	-		$	2,310,329
	Shareholders' Equity
	Common shares	$	279		$	-		$	8,000		$	(8,000	)	$	279
	Additional paid-in capital		-			214,660			2,022,889			(2,237,549	)		-
	Accumulated other comprehensive income		57,390			20,252			77,638			(97,890	)		57,390
	Retained earnings		1,641,261			339,737			239,324			(579,061	)		1,641,261
	Total shareholders' equity	$	1,698,930		$	574,649		$	2,347,851		$	(2,922,500	)	$	1,698,930
	Total liabilities and shareholders' equity	$	1,707,378		$	830,983		$	4,393,398		$	(2,922,500	)	$	4,009,259
	(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
	Condensed Consolidating Balance Sheet
	31-Dec-12
		Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
	ASSETS
	Total investments	$	-		$	181		$	2,227,118		$	-		$	2,227,299
	Investment in subsidiaries		1,821,818			636,814			540,354			(2,998,986	)		-
	Cash and cash equivalents		70,604			152,122			1,497,669			-			1,720,395
	Reinsurance assets		-			-			277,279			-			277,279
	Other assets		8,997			2,884			96,449			-			108,330
	Total assets	$	1,901,419		$	792,001		$	4,638,869		$	(2,998,986	)	$	4,333,303
	LIABILITIES AND SHAREHOLDERS' EQUITY
	Liabilities
	Reinsurance liabilities	$	-		$	-		$	2,140,241		$	-		$	2,140,241
	Debt obligations		-			250,000			-			-			250,000
	Other liabilities		6,885			1,647			39,996			-			48,528
	Total liabilities	$	6,885		$	251,647		$	2,180,237		$	-		$	2,438,769
	Shareholders' Equity
	Common shares	$	327		$	-		$	8,000		$	(8,000	)	$	327
	Additional paid-in capital		209,897			213,736			2,021,045			(2,234,781	)		209,897
	Accumulated other comprehensive income		137,690			41,386			179,071			(220,457	)		137,690
	Retained earnings		1,546,620			285,232			250,516			(535,748	)		1,546,620
	Total shareholders' equity	$	1,894,534		$	540,354		$	2,458,632		$	(2,998,986	)	$	1,894,534
	Total liabilities and shareholders' equity	$	1,901,419		$	792,001		$	4,638,869		$	(2,998,986	)	$	4,333,303
	(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
	Condensed Consolidating Statement of Operations
	For the Three Months Ended September 30, 2013
		Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
	Revenue:
	Net premiums earned	$	-		$	-		$	135,360		$	-		$	135,360
	Net investment income (expense)		1			(43	)		17,800			-			17,758
	Net realized gains (losses) on investments		-			-			(306	)		-			(306	)
	Net impairment losses on investments		-			-			(65	)		-			(65	)
	Other income (expense)		1,149			-			277			-			1,426
	Total revenue		1,150			(43	)		153,066			-			154,173
	Expenses:
	Net losses and loss adjustment expenses		-			-			44,142			-			44,142
	Net acquisition expenses		-			-			30,675			-			30,675
Operating expenses		6,626			37			14,009			-			20,672
Net foreign currency exchange losses (gains)		-			-			487			-			487
Interest expense		-			4,782			-			-			4,782
Total expenses		6,626			4,819			89,313			-			100,758
Income (loss) before income taxes		(5,476	)		(4,862	)		63,753			-			53,415
Income tax expense (benefit)		-			(1,589	)		16,719			-			15,130
Income (loss) before equity in earnings of subsidiaries		(5,476	)		(3,273	)		47,034			-			38,285
Equity in earnings of subsidiaries		43,761			29,948			26,675			(100,384	)		-
Net income	$	38,285		$	26,675		$	73,709		$	(100,384	)	$	38,285
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Operations
For the Three Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Revenue:
Net premiums earned	$	-		$	-		$	138,588		$	-		$	138,588
Net investment income (expense)		2			(3	)		23,210			-			23,209
Net realized gains (losses) on investments		-			-			22,982			-			22,982
Net impairment losses on investments		-			-			(699	)		-			(699	)
Other income (expense)		1,400			1			(1,497	)		-			(96	)
Total revenue		1,402			(2	)		182,584			-			183,984
Expenses:
Net losses and loss adjustment expenses		-			-			45,117			-			45,117
Net acquisition expenses		-			-			26,168			-			26,168
Operating expenses		5,842			49			14,075			-			19,966
Net foreign currency exchange losses (gains)		-			-			541			-			541
Interest expense		-			4,775			-			-			4,775
Total expenses		5,842			4,824			85,901			-			96,567
Income (loss) before income taxes		(4,440	)		(4,826	)		96,683			-			87,417
Income tax expense (benefit)		-			(1,625	)		4,178			-			2,553
Income (loss) before equity in earnings of subsidiaries		(4,440	)		(3,201	)		92,505			-			84,864
Equity in earnings of subsidiaries		89,304			8,175			4,974			(102,453	)		-
Net income	$	84,864		$	4,974		$	97,479		$	(102,453	)	$	84,864
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Operations
For the Nine Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Revenue:
Net premiums earned	$	-		$	-		$	405,146		$	-		$	405,146
Net investment income (expense)		23			(73	)		54,160			-			54,110
Net realized gains on investments		-			-			24,698			-			24,698
Net impairment losses on investments		-			-			(2,002	)		-			(2,002	)
Other income (expense)		5,994			4			(3,495	)		-			2,503
Total revenue		6,017			(69	)		478,507			-			484,455
Expenses:
Net losses and loss adjustment expenses		-			-			120,807			-			120,807
Net acquisition expenses		-			-			91,207			-			91,207
Operating expenses		18,427			110			41,158			-			59,695
Net foreign currency exchange losses (gains)		-			-			(592	)		-			(592	)
Interest expense		-			14,341			-			-			14,341
Total expenses		18,427			14,451			252,580			-			285,458
Income (loss) before income taxes		(12,410	)		(14,520	)		225,927			-			198,997
Income tax expense (benefit)		-			(4,785	)		29,127			-			24,342
Income (loss) before equity in earnings of subsidiaries		(12,410	)		(9,735	)		196,800			-			174,655
Equity in earnings of subsidiaries		187,065			64,241			54,506			(305,812	)		-
Net income	$	174,655		$	54,506		$	251,306		$	(305,812	)	$	174,655
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Operations
For the Nine Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Revenue:
Net premiums earned	$	-		$	-		$	421,875		$	-		$	421,875
Net investment income (expense)		5			(10	)		77,921			-			77,916
Net realized gains on investments		-			-			70,299			-			70,299
Net impairment losses on investments		-			-			(2,882	)		-			(2,882	)
Other income (expense)		3,587			2			(4,355	)		-			(766	)
Total revenue		3,592			(8	)		562,858			-			566,442
Expenses:
Net losses and loss adjustment expenses		-			-			191,430			-			191,430
Net acquisition expenses		-			-			87,025			-			87,025
Operating expenses		16,617			182			39,846			-			56,645
Net foreign currency exchange losses (gains)		-			-			763			-			763
Interest expense		-			14,321			-			-			14,321
Total expenses		16,617			14,503			319,064			-			350,184
Income (loss) before income taxes		(13,025	)		(14,511	)		243,794			-			216,258
Income tax expense (benefit)		-			(4,890	)		15,465			-			10,575
Income (loss) before equity in earnings of subsidiaries		(13,025	)		(9,621	)		228,329			-			205,683
Equity in earnings of subsidiaries		218,708			40,116			30,495			(289,319	)		-
Net income	$	205,683		$	30,495		$	258,824		$	(289,319	)	$	205,683
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Three Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	38,285		$	26,675		$	73,709		$	(100,384	)	$	38,285
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			14			-			14
Change in net unrealized gains and losses on all other securities		-			-			(7,622	)		-			(7,622	)
Total change in net unrealized gains and losses		-			-			(7,608	)		-			(7,608	)
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			-			-			-
Net impairment losses on investments		-			-			65			-			65
Total reclassifications to net income		-			-			65			-			65
Other comprehensive income (loss) before income taxes		-			-			(7,543	)		-			(7,543	)
Income tax benefit (expense)		-			(1	)		567			-			566
Other comprehensive income (loss)		-			(1	)		(6,976	)		-			(6,977	)
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		(6,977	)		(1,049	)		(1,050	)		9,076			-
Comprehensive income	$	31,308		$	25,625		$	65,683		$	(91,308	)	$	31,308
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Three Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	84,864		$	4,974		$	97,479		$	(102,453	)	$	84,864
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			354			-			354
Change in net unrealized gains and losses on all other securities		-			(2	)		24,213			-			24,211
Total change in net unrealized gains and losses		-			(2	)		24,567			-			24,565
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			(22,710	)		-			(22,710	)
Net impairment losses on investments		-			-			699			-			699
Total reclassifications to net income		-			-			(22,011	)		-			(22,011	)
Other comprehensive income (loss) before income taxes		-			(2	)		2,556			-			2,554
Income tax benefit (expense)		-			1			(730	)		-			(729	)
Other comprehensive income (loss)		-			(1	)		1,826			-			1,825
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		1,825			1,356			1,355			(4,536	)		-
Comprehensive income	$	86,689		$	6,329		$	100,660		$	(106,989	)	$	86,689
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Nine Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	174,655		$	54,506		$	251,306		$	(305,812	)	$	174,655
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			(600	)		-			(600	)
Change in net unrealized gains and losses on all other securities		-			(2	)		(65,837	)		-			(65,839	)
Total change in net unrealized gains and losses		-			(2	)		(66,437	)		-			(66,439	)
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			(27,243	)		-			(27,243	)
Net impairment losses on investments		-			-			2,002			-			2,002
Total reclassifications to net income		-			-			(25,241	)		-			(25,241	)
Other comprehensive income (loss) before income taxes		-			(2	)		(91,678	)		-			(91,680	)
Income tax benefit (expense)		-			1			11,379			-			11,380
Other comprehensive income (loss)		-			(1	)		(80,299	)		-			(80,300	)
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		(80,300	)		(21,133	)		(21,134	)		122,567			-
Comprehensive income	$	94,355		$	33,372		$	149,873		$	(183,245	)	$	94,355
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Nine Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	205,683		$	30,495		$	258,824		$	(289,319	)	$	205,683
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			263			-			263
Change in net unrealized gains and losses on all other securities		-			(3	)		73,307			-			73,304
Total change in net unrealized gains and losses		-			(3	)		73,570			-			73,567
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			(70,607	)		-			(70,607	)
Net impairment losses on investments		-			-			2,882			-			2,882
Total reclassifications to net income		-			-			(67,725	)		-			(67,725	)
Other comprehensive income (loss) before income taxes		-			(3	)		5,845			-			5,842
Income tax benefit (expense)		-			2			(2,092	)		-			(2,090	)
Other comprehensive income (loss)		-			(1	)		3,753			-			3,752
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		3,752			3,883			3,882			(11,517	)		-
Comprehensive income	$	209,435		$	34,377		$	266,459		$	(300,836	)	$	209,435
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Cash Flows
For the Nine Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net cash provided by (used in) operating activities	$	(8,724	)	$	(3,970	)	$	(481	)	$	(923	)	$	(14,098	)
Investing Activities:
Proceeds from the sales of:
Fixed maturity available-for-sale securities		-			-			203,571			-			203,571
Short-term investments		-			-			11,857			-			11,857
Proceeds from the maturities or paydowns of:
Fixed maturity available-for-sale securities		-			52			155,194			-			155,246
Short-term investments		-			-			209,240			-			209,240
Acquisitions of:
Fixed maturity available-for-sale securities		-			-			(291,006	)		-			(291,006	)
Short-term investments		-			-			(121,306	)		-			(121,306	)
Dividends from subsidiaries		262,500			-			-			(262,500	)		-
Acquisitions of furniture, equipment and other assets		(772	)		-			(5,416	)		-			(6,188	)
Net cash provided by (used in) investing activities		261,728			52			162,134			(262,500	)		161,414
Financing Activities:
Dividends paid to common shareholders		(7,181	)		-			(262,500	)		262,500			(7,181	)
Repurchase of common shares		(302,765	)		-			-			-			(302,765	)
Proceeds from share-based compensation, including income tax benefits		14,462			-			-			923			15,385
Net cash provided by (used in) financing activities		(295,484	)		-			(262,500	)		263,423			(294,561	)
Effect of foreign currency exchange rate changes on cash and cash equivalents		-			-			(7,745	)		-			(7,745	)
Net increase (decrease) in cash and cash equivalents		(42,480	)		(3,918	)		(108,592	)		-			(154,990	)
Cash and cash equivalents at beginning of period		70,604			152,122			1,497,669			-			1,720,395
Cash and cash equivalents at end of period	$	28,124		$	148,204		$	1,389,077		$	-		$	1,565,405
Condensed Consolidating Statement of Cash Flows
For the Nine Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net cash provided by (used in) operating activities	$	(7,874	)	$	(3,507	)	$	(7,588	)	$	-		$	(18,969	)
Investing Activities:
Proceeds from the sales of:
Fixed maturity available-for-sale securities		-			-			558,848			-			558,848
Short-term investments		-			-			36,581			-			36,581
Proceeds from the maturities or paydowns of:
Fixed maturity available-for-sale securities		-			63			213,440			-			213,503
Short-term investments		-			-			663,011			-			663,011
Acquisitions of:
Fixed maturity available-for-sale securities		-			-			(202,729	)		-			(202,729	)
Short-term investments		-			-			(266,723	)		-			(266,723	)
Dividends from subsidiaries		120,000			-			-			(120,000	)		-
Net cash provided by (used in) investing activities		120,000			63			1,002,428			(120,000	)		1,002,491
Financing Activities:
Dividends paid to common shareholders		(8,137	)		-			(120,000	)		120,000			(8,137	)
Repurchase of common shares		(109,633	)		-			-			-			(109,633	)
Proceeds from share-based compensation, including income tax benefits		2,554			-			-			-			2,554
Net cash provided by (used in) financing activities		(115,216	)		-			(120,000	)		120,000			(115,216	)
Effect of foreign currency exchange rate changes on cash and cash equivalents		-			-			1,863			-			1,863
Net increase (decrease) in cash and cash equivalents		(3,090	)		(3,444	)		876,703			-			870,169
Cash and cash equivalents at beginning of period		47,791			108,260			636,459			-			792,510
Cash and cash equivalents at end of period	$	44,701		$	104,816		$	1,513,162		$	-		$	1,662,679

Basis_of_Presentation_and_Sign1

Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Basis of Presentation and Significant Accounting Policies [Abstract]
Nature of operations	Platinum Underwriters Holdings, Ltd. (“Platinum Holdings”) is a holding company domiciled in Bermuda. Through our reinsurance subsidiaries, we provide property and marine, casualty and finite risk reinsurance coverages to a diverse clientele of insurers and select reinsurers on a worldwide basis.
Consolidation policy	Platinum Holdings and its consolidated subsidiaries (collectively, the “Company”) include Platinum Holdings, Platinum Underwriters Bermuda, Ltd. (“Platinum Bermuda”), Platinum Underwriters Reinsurance, Inc. (“Platinum US”), Platinum Regency Holdings (“Platinum Regency”), Platinum Underwriters Finance, Inc. (“Platinum Finance”) and Platinum Administrative Services, Inc. The terms “we,” “us,” and “our” refer to the Company, unless the context otherwise indicates.
	We operate through two licensed reinsurance subsidiaries, Platinum Bermuda, a Bermuda reinsurance company, and Platinum US, a U.S. reinsurance company. Platinum Regency is an intermediate holding company based in Ireland and a wholly owned subsidiary of Platinum Holdings. Platinum Finance is an intermediate holding company based in the U.S. and a wholly owned subsidiary of Platinum Regency. Platinum Bermuda is a wholly owned subsidiary of Platinum Holdings and Platinum US is a wholly owned subsidiary of Platinum Finance. Platinum Administrative Services, Inc. is a wholly owned subsidiary of Platinum Finance that provides administrative support services to the Company.
	The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information. Accordingly, they do not include all the information and footnotes required by U.S. GAAP for complete financial statements. All material inter-company transactions and accounts have been eliminated in preparing these consolidated financial statements. The consolidated financial statements as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 are unaudited and include all adjustments consisting of normal recurring items that management considers necessary for a fair presentation under U.S. GAAP. These consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2012.
Use of estimates	The preparation of financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ materially from these estimates. The major estimates used in the preparation of the Company's consolidated financial statements, and therefore considered to be critical accounting estimates, include, but are not limited to, premiums written and earned, unpaid losses and loss adjustment expenses (“LAE”), valuation of investments and income taxes. In addition, estimates are used in our risk transfer analysis for assumed and ceded reinsurance transactions. Results of changes in estimates are reflected in results of operations in the period in which the change is made. The results of operations for any interim period are not necessarily indicative of results for the full year.
Recently issued accounting standards	In February 2013, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (“ASU 2013-02”). ASU 2013-02 supersedes and replaces the presentation requirements for reclassifications out of accumulated other comprehensive income in ASU 2011-12 “Comprehensive Income: Deferral of the Effective Date for Amendments to the Presentation of Reclassification of Items Out of Accumulated Other Comprehensive Income in Accounting Standards Update No. 2011-05” and ASU 2011-05 “Presentation of Comprehensive Income” and requires additional information about reclassifications out of accumulated other comprehensive income. None of the other requirements of the previous ASUs are affected by ASU 2013-02. ASU 2013-02 is effective on a prospective basis for interim and annual periods beginning after December 15, 2012. We adopted the guidance as of January 1, 2013 with additional disclosures reflected in Note 10.

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Investments [Abstract]
Fixed maturity available-for-sale securities	Our fixed maturity available-for-sale securities are U.S. dollar denominated securities. The following table sets forth our fixed maturity available-for-sale securities as of September 30, 2013 and December 31, 2012 ($ in thousands):
							Included in Accumulated Other Comprehensive Income
			Amortized Cost				Gross Unrealized Gains				Gross Unrealized Losses				Fair Value			Non-credit portion of OTTI(1)
	September 30, 2013:
	U.S. Government		$	4,579			$	230			$	-			$	4,809		$	-
	Municipal bonds			1,217,511				62,751				5,453				1,274,809			-
	Non-U.S. governments			39,971				541				-				40,512			-
	Corporate bonds			226,835				7,023				3,016				230,842			-
	Commercial mortgage-backed securities			83,270				5,126				292				88,104			-
	Residential mortgage-backed securities			178,662				1,500				1,367				178,795			502
	Asset-backed securities			16,257				1,609				357				17,509			286
	Total fixed maturity available-for-sale securities		$	1,767,085			$	78,780			$	10,485			$	1,835,380		$	788
	December 31, 2012:
	U.S. Government		$	4,632			$	312			$	-			$	4,944		$	-
	Municipal bonds			1,080,273				129,735				74				1,209,934			-
	Non-U.S. governments			49,978				999				-				50,977			-
	Corporate bonds			279,981				21,109				182				300,908			-
	Commercial mortgage-backed securities			127,148				8,807				429				135,526			264
	Residential mortgage-backed securities			222,331				2,584				3,293				221,622			2,083
	Asset-backed securities			17,206				1,426				858				17,774			858
	Total fixed maturity available-for-sale securities		$	1,781,549			$	164,972			$	4,836			$	1,941,685		$	3,205
	(1)        The non-credit portion of other than temporary impairments ("OTTI") represents the amount of unrealized losses on impaired securities that were not recorded in the consolidated statements of operations as of the reporting date. These unrealized losses are included in gross unrealized losses as of September 30, 2013 and December 31, 2012.
Fair value of fixed maturity trading securities	The following table sets forth the fair value of our fixed maturity trading securities as of September 30, 2013 and December 31, 2012 ($ in thousands):
			30-Sep-13				December 31, 2012
	Non-U.S. governments		$	102,604			$	112,813
	Total fixed maturity trading securities		$	102,604			$	112,813
Contractual maturities of fixed maturity available-for-sale securities and trading securities	The following table sets forth the amortized cost and fair value of our fixed maturity available-for-sale and trading securities by stated maturity as of September 30, 2013 ($ in thousands):
			Amortized Cost				Fair Value
	Due in one year or less		$	41,124			$	41,612
	Due from one to five years			475,473				495,931
	Due from five to ten years			658,273				681,902
	Due in ten or more years			410,416				434,131
	Mortgage-backed and asset-backed securities			278,189				284,408
	Total		$	1,863,475			$	1,937,984
Fair value of short-term investments	The following table sets forth the fair value of our short-term investments as of September 30, 2013 and December 31, 2012 ($ in thousands):
			30-Sep-13				December 31, 2012
	Available-for-sale:
	U.S. Government		$	-			$	49,186
	Trading:
	Non-U.S. governments			73,635				123,615
	Total short-term investments		$	73,635			$	172,801
Net impairment losses on investments	The following table sets forth the net impairment losses on investments for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
	Commercial mortgage-backed securities		$	-			$	-			$	-			$	30
	Non-agency residential mortgage-backed securities			28				693				1,439				2,839
	Sub-prime asset-backed securities			37				6				563				13
	Net impairment losses on investments		$	65			$	699			$	2,002			$	2,882
Summary of cumulative credit losses recognized on fixed maturity available-for-sale securities	The following table sets forth a summary of the cumulative credit losses recognized on our fixed maturity available-for-sale securities for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
	Balance, beginning of period		$	35,762			$	57,874			$	40,219			$	61,841
	Credit losses on securities not previously impaired			-				42				-				42
	Credit losses on securities previously impaired			65				657				2,002				2,840
	Reduction for paydowns and securities sold			(2,956	)			(3,447	)			(9,094	)			(9,168	)
	Reduction for increases in cash flows expected to be collected			(195	)			(309	)			(451	)			(738	)
	Balance, end of period		$	32,676			$	54,817			$	32,676			$	54,817
Gross unrealized losses on fixed maturity securities classified as available-for-sale	The following table sets forth our gross unrealized losses on securities classified as fixed maturity available-for-sale aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2013 and December 31, 2012 ($ in thousands):
			30-Sep-13								December 31, 2012
			Fair Value				Unrealized Loss				Fair Value				Unrealized Loss
	Less than twelve months:
	Municipal bonds		$	207,187			$	5,453			$	18,878			$	74
	Corporate bonds			85,865				3,016				4,450				41
	Commercial mortgage-backed securities			4,463				292				6,758				165
	Residential mortgage-backed securities			28,640				162				39				9
	Asset-backed securities			13,529				71				64				1
	Total		$	339,684			$	8,994			$	30,189			$	290
	Twelve months or more:
	Municipal bonds		$	-			$	-			$	-			$	-
	Corporate bonds			-				-				6,039				141
	Commercial mortgage-backed securities			-				-				762				264
	Residential mortgage-backed securities			14,572				1,205				17,096				3,284
	Asset-backed securities			772				286				799				857
	Total		$	15,344			$	1,491			$	24,696			$	4,546
	Total unrealized losses:
	Municipal bonds		$	207,187			$	5,453			$	18,878			$	74
	Corporate bonds			85,865				3,016				10,489				182
	Commercial mortgage-backed securities			4,463				292				7,520				429
	Residential mortgage-backed securities			43,212				1,367				17,135				3,293
	Asset-backed securities			14,301				357				863				858
	Total		$	355,028			$	10,485			$	54,885			$	4,836
Net investment income	The following table sets forth our net investment income for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013				2012				2013				2012
	Fixed maturity securities	$	16,815			$	22,022			$	51,428			$	73,892
	Short-term investments and cash and cash equivalents		1,123				1,547				3,346				5,358
	Funds held by ceding companies		722				684				2,375				1,938
	Subtotal		18,660				24,253				57,149				81,188
	Investment expenses		(902	)			(1,044	)			(3,039	)			(3,272	)
	Net investment income	$	17,758			$	23,209			$	54,110			$	77,916
Net realized gains and losses on investments	The following table sets forth our net realized gains (losses) on investments for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013				2012				2013				2012
	Gross realized gains on the sale of investments	$	-			$	22,979			$	27,258			$	70,920
	Gross realized losses on the sale of investments		-				-				(15	)			(1	)
	Net realized gains on the sale of investments		-				22,979				27,243				70,919
	Fair value adjustments on trading securities		(306	)			3				(2,545	)			(620	)
	Net realized gains (losses) on investments	$	(306	)		$	22,982			$	24,698			$	70,299

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Measurements [Abstract]
Fair value measurement of assets and liabilities	The following table presents the fair value hierarchy for those financial assets and liabilities measured at fair value on a recurring basis by the Company as of September 30, 2013 and December 31, 2012 ($ in thousands):
					Fair Value Measurement Using:
		Total			Level 1			Level 2			Level 3
	September 30, 2013:
	Investments:
	U.S. Government	$	4,809		$	4,809		$	-		$	-
	Municipal bonds		1,274,809			-			1,274,809			-
	Non-U.S. governments		143,116			54,437			88,679			-
	Corporate bonds		230,842			-			230,842			-
	Commercial mortgage-backed securities		88,104			-			88,104			-
	Residential mortgage-backed securities		178,795			-			178,280			515
	Asset-backed securities		17,509			-			14,949			2,560
	Short-term investments		73,635			-			73,635			-
	Total investments		2,011,619			59,246			1,949,298			3,075
	Reinsurance deposit assets		78,179			-			-			78,179
	Total	$	2,089,798		$	59,246		$	1,949,298		$	81,254
	December 31, 2012:
	Investments:
	U.S. Government	$	4,944		$	4,944		$	-		$	-
	Municipal bonds		1,209,934			-			1,209,934			-
	Non-U.S. governments		163,790			56,422			107,368			-
	Corporate bonds		300,908			-			300,908			-
	Commercial mortgage-backed securities		135,526			-			135,002			524
	Residential mortgage-backed securities		221,622			-			216,248			5,374
	Asset-backed securities		17,774			-			16,738			1,036
	Short-term investments		172,801			-			172,801			-
	Total investments		2,227,299			61,366			2,158,999			6,934
	Reinsurance deposit asset		50,693			-			-			50,693
	Total	$	2,277,992		$	61,366		$	2,158,999		$	57,627
Fair value assets measured on recurring basis unobservable input reconciliation	The following table reconciles the beginning and ending balance for our Level 3 financial assets measured at fair value on a recurring basis for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended September 30, 2013
		Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
	Balance, beginning of period	$	-		$	4,520		$	1,257		$	76,948	$	82,725
	Sales, maturities and paydowns		-			(269	)		-			-		(269	)
	Total increase (decrease) in fair value included in earnings		-			-			-			1,231		1,231
	Total net unrealized gains (losses) included in other comprehensive income (loss)		-			329			(75	)		-		254
	Transfers into Level 3		-			-			1,378			-		1,378
	Transfers out of Level 3		-			(4,065	)		-			-		(4,065	)
	Balance, end of period	$	-		$	515		$	2,560		$	78,179	$	81,254
	Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	1,231	$	1,231
		Three Months Ended September 30, 2012
		Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
	Balance, beginning of period	$	-		$	7,461		$	1,566		$	-	$	9,027
	Sales, maturities and paydowns		-			(935	)		-			-		(935	)
	Total net unrealized gains (losses) included in other comprehensive income (loss)		-			1,789			(30	)		-		1,759
	Transfers into Level 3		-			3,807			4,932			-		8,739
	Transfers out of Level 3		-			(3,915	)		(399	)		-		(4,314	)
	Balance, end of period	$	-		$	8,207		$	6,069		$	-	$	14,276
	Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	-	$	-
		Nine Months Ended September 30, 2013
		Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
	Balance, beginning of period	$	524		$	5,374		$	1,036		$	50,693	$	57,627
	Purchases		-			-			-			25,000		25,000
	Sales, maturities and paydowns		-			(435	)		(29	)		-		(464	)
	Total increase (decrease) in fair value included in earnings		-			-			-			2,486		2,486
	Total net unrealized gains (losses) included in other comprehensive income (loss)		487			750			(46	)		-		1,191
	Transfers into Level 3		-			4,049			3,984			-		8,033
	Transfers out of Level 3		(1,011	)		(9,223	)		(2,385	)		-		(12,619	)
	Balance, end of period	$	-		$	515		$	2,560		$	78,179	$	81,254
	Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	2,486	$	2,486
		Nine Months Ended September 30, 2012
		Commercial mortgage-backed securities			Residential mortgage-backed securities			Asset-backed securities			Reinsurance deposit assets		Total
	Balance, beginning of period	$	-		$	8,146		$	1,867		$	-	$	10,013
	Sales, maturities and paydowns		-			(1,669	)		-			-		(1,669	)
	Total net unrealized gains (losses) included in other comprehensive income (loss)		-			1,839			(331	)		-		1,508
	Transfers into Level 3		-			6,060			4,932			-		10,992
	Transfers out of Level 3		-			(6,169	)		(399	)		-		(6,568	)
	Balance, end of period	$	-		$	8,207		$	6,069		$	-	$	14,276
	Total increase (decrease) in fair value of the financial assets included in earnings for the period	$	-		$	-		$	-		$	-	$	-
Fair value assets quantitative information	The following table sets forth the weighted average of the significant unobservable quantitative information used for the fair value measurement of our reinsurance deposit assets as of September 30, 2013 and December 31, 2012:
		30-Sep-13			31-Dec-12
	Estimated contract period remaining		1,282 days			1,350 days
	Credit spread above the risk-free rate		1.84	%		2.47	%
	Net losses and LAE ceded inception-to-date	$	-		$	-

Credit_Facilities_Tables

Credit Facilities (Tables)	9 Months Ended
	Sep. 30, 2013
Credit Facilities [Abstract]
Schedule of line of credit facilities	The following table summarizes the outstanding LOC and the cash and cash equivalents held in trust to collateralize LOC issued as of September 30, 2013 ($ in thousands):
		Letters of Credit				Collateral
		Committed Capacity		Issued		Cash and Cash Equivalents
	Syndicated Credit Facility:
	Secured	$	200,000	$	80,405	$	93,356
	Unsecured		100,000		-		-
	Total Syndicated Credit Facility		300,000		80,405		93,356
	Other LOC Facilities		115,405		44,068		67,317
	Total	$	415,405	$	124,473	$	160,673

Statutory_Regulations_and_Divi1

Statutory Regulations and Dividend Restrictions (Tables)	9 Months Ended
	Sep. 30, 2013
Statutory Regulations And Dividend Restrictions [Abstract]
Maximum dividends payable and amounts paid	The laws and regulations of Bermuda and the United States include certain restrictions on the amount of statutory capital and surplus that are available for the payment of dividends by Platinum Bermuda and Platinum US to their respective parent companies, Platinum Holdings and Platinum Finance, without the prior approval of the relevant regulatory authorities. The following table summarizes the dividend capacity of our reinsurance subsidiaries for 2013 ($ in thousands):
		2013		For the Nine Months Ended September 30, 2013		30-Sep-13
		Dividend Capacity		Paid		Remaining
	Platinum Bermuda	$	318,343	$	262,500	$	55,843
	Platinum US		30,779		-		30,779
	Total	$	349,122	$	262,500	$	86,622

Operating_Segment_Information_

Operating Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Operating Segment Information [Abstract]
Operating segment underwriting activity, ratios and income reconciliation	The following table summarizes underwriting activity and ratios for the three operating segments, together with a reconciliation of segment underwriting income (loss) to the U.S. GAAP measure of income before income taxes for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended September 30, 2013
		Property and Marine			Casualty			Finite Risk			Total
	Net premiums written	$	59,169		$	69,992		$	8,737		$	137,898
	Net premiums earned		55,127			72,543			7,690			135,360
	Net losses and loss adjustment expenses		28,339			10,242			5,561			44,142
	Net acquisition expenses		9,699			19,067			1,909			30,675
	Other underwriting expenses		7,747			5,727			342			13,816
	Segment underwriting income (loss)	$	9,342		$	37,507		$	(122	)		46,727
	Net investment income											17,758
	Net realized gains (losses) on investments											(306	)
	Net impairment losses on investments											(65	)
	Other income (expense)											1,426
	Corporate expenses not allocated to segments											(6,856	)
	Net foreign currency exchange (losses) gains											(487	)
	Interest expense											(4,782	)
	Income before income taxes										$	53,415
	Underwriting ratios:
	Net loss and loss adjustment expense		51.4	%		14.1	%		72.3	%		32.6	%
	Net acquisition expense		17.6	%		26.3	%		24.8	%		22.7	%
	Other underwriting expense		14.1	%		7.9	%		4.4	%		10.2	%
	Combined		83.1	%		48.3	%		101.5	%		65.5	%
		Three Months Ended September 30, 2012
		Property and Marine			Casualty			Finite Risk			Total
	Net premiums written	$	64,876		$	72,358		$	8,745		$	145,979
	Net premiums earned		61,900			70,326			6,362			138,588
	Net losses and loss adjustment expenses		26,790			14,358			3,969			45,117
	Net acquisition expenses		7,078			16,710			2,380			26,168
	Other underwriting expenses		7,661			5,662			289			13,612
	Segment underwriting income (loss)	$	20,371		$	33,596		$	(276	)		53,691
	Net investment income											23,209
	Net realized gains (losses) on investments											22,982
	Net impairment losses on investments											(699	)
	Other income (expense)											(96	)
	Corporate expenses not allocated to segments											(6,354	)
	Net foreign currency exchange (losses) gains											(541	)
	Interest expense											(4,775	)
	Income before income taxes										$	87,417
	Underwriting ratios:
	Net loss and loss adjustment expense		43.3	%		20.4	%		62.4	%		32.6	%
	Net acquisition expense		11.4	%		23.8	%		37.4	%		18.9	%
	Other underwriting expense		12.4	%		8.1	%		4.5	%		9.8	%
	Combined		67.1	%		52.3	%		104.3	%		61.3	%
		Nine Months Ended September 30, 2013
		Property and Marine			Casualty			Finite Risk			Total
	Net premiums written	$	175,946		$	220,547		$	22,540		$	419,033
	Net premiums earned		165,811			218,967			20,368			405,146
	Net losses and loss adjustment expenses		35,426			75,243			10,138			120,807
	Net acquisition expenses		27,624			53,384			10,199			91,207
	Other underwriting expenses		22,493			17,120			1,002			40,615
	Segment underwriting income (loss)	$	80,268		$	73,220		$	(971	)		152,517
	Net investment income											54,110
	Net realized gains on investments											24,698
	Net impairment losses on investments											(2,002	)
	Other income (expense)											2,503
	Corporate expenses not allocated to segments											(19,080	)
	Net foreign currency exchange (losses) gains											592
	Interest expense											(14,341	)
	Income before income taxes										$	198,997
	Underwriting ratios:
	Net loss and loss adjustment expense		21.4	%		34.4	%		49.8	%		29.8	%
	Net acquisition expense		16.7	%		24.4	%		50.1	%		22.5	%
	Other underwriting expense		13.6	%		7.8	%		4.9	%		10	%
	Combined		51.7	%		66.6	%		104.8	%		62.3	%
	Nine Months Ended September 30, 2012
	Property and Marine			Casualty			Finite Risk			Total
Net premiums written	$	194,724		$	219,436		$	16,939		$	431,099
Net premiums earned		186,066			221,838			13,971			421,875
Net losses and loss adjustment expenses		85,380			101,245			4,805			191,430
Net acquisition expenses		25,034			52,572			9,419			87,025
Other underwriting expenses		21,950			16,323			747			39,020
Segment underwriting income (loss)	$	53,702		$	51,698		$	(1,000	)		104,400
Net investment income											77,916
Net realized gains on investments											70,299
Net impairment losses on investments											(2,882	)
Other income (expense)											(766	)
Corporate expenses not allocated to segments											(17,625	)
Net foreign currency exchange (losses) gains											(763	)
Interest expense											(14,321	)
Income before income taxes										$	216,258
Underwriting ratios:
Net loss and loss adjustment expense		45.9	%		45.6	%		34.4	%		45.4	%
Net acquisition expense		13.5	%		23.7	%		67.4	%		20.6	%
Other underwriting expense		11.8	%		7.4	%		5.3	%		9.2	%
Combined		71.2	%		76.7	%		107.1	%		75.2	%

Earnings_Loss_Per_Common_Share1

Earnings (Loss) Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings (Loss) Per Common Share [Abstract]
Reconciliation of basic and diluted earnings or loss per common share	The following is a reconciliation of basic and diluted earnings per common share for the three and nine months ended September 30, 2013 and 2012 ($ and amounts in thousands, except per share data):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	Earnings
	Basic and Diluted
	Net income attributable to common shareholders	$	38,285		$	84,864		$	174,655		$	205,683
	Portion allocated to participating common shareholders (1)		(26	)		(234	)		(301	)		(740	)
	Net income allocated to common shareholders	$	38,259		$	84,630		$	174,354		$	204,943
	Common Shares
	Basic
	Weighted average common shares outstanding		28,655			32,996			30,519			34,063
	Diluted
	Weighted average common shares outstanding		28,655			32,996			30,519			34,063
	Effect of dilutive securities:
	Common share options		131			179			173			154
	Restricted share units		279			97			257			69
	Adjusted weighted average common shares outstanding		29,065			33,272			30,949			34,286
	Earnings Per Common Share
	Basic earnings per common share	$	1.34		$	2.56		$	5.71		$	6.02
	Diluted earnings per common share	$	1.32		$	2.54		$	5.63		$	5.98
	(1)        Represents earnings attributable to holders of unvested restricted shares issued under the Company's share incentive plans that are considered to be participating securities. In July 2013, the remaining outstanding restricted shares vested and therefore there were no unvested restricted shares as of September 30, 2013.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income [Abstract]
Schedule of beginning and ending balances for accumulated other comprehensive income	The following table reconciles the beginning and ending balances for accumulated other comprehensive income for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		Three Months Ended September 30, 2013
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	75,838		$	(11,471	)	$	64,367
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		14			-			14
	Change in net unrealized gains and losses on all other securities		(7,622	)		566			(7,056	)
	Total change in net unrealized gains and losses		(7,608	)		566			(7,042	)
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		-			-			-
	Net impairment losses on investments		65			-			65
	Total reclassifications to net income		65			-			65
	Other comprehensive income (loss)		(7,543	)		566			(6,977	)
	Balance, end of period	$	68,295		$	(10,905	)	$	57,390
		Three Months Ended September 30, 2012
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	172,149		$	(23,587	)	$	148,562
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		354			19			373
	Change in net unrealized gains and losses on all other securities		24,211			(3,181	)		21,030
	Total change in net unrealized gains and losses		24,565			(3,162	)		21,403
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		(22,710	)		2,466			(20,244	)
	Net impairment losses on investments		699			(33	)		666
	Total reclassifications to net income		(22,011	)		2,433			(19,578	)
	Other comprehensive income (loss)		2,554			(729	)		1,825
	Balance, end of period	$	174,703		$	(24,316	)	$	150,387
		Nine Months Ended September 30, 2013
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	159,975		$	(22,285	)	$	137,690
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		(600	)		11			(589	)
	Change in net unrealized gains and losses on all other securities		(65,839	)		7,727			(58,112	)
	Total change in net unrealized gains and losses		(66,439	)		7,738			(58,701	)
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		(27,243	)		3,675			(23,568	)
	Net impairment losses on investments		2,002			(33	)		1,969
	Total reclassifications to net income		(25,241	)		3,642			(21,599	)
	Other comprehensive income (loss)		(91,680	)		11,380			(80,300	)
	Balance, end of period	$	68,295		$	(10,905	)	$	57,390
		Nine Months Ended September 30, 2012
		Pre-tax			Tax			Net of tax
	Balance, beginning of period	$	168,861		$	(22,226	)	$	146,635
	Other comprehensive income (loss) on available-for-sale securities before reclassifications:
	Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		263			79			342
	Change in net unrealized gains and losses on all other securities		73,304			(6,124	)		67,180
	Total change in net unrealized gains and losses		73,567			(6,045	)		67,522
	Reclassifications to net income on available-for-sale securities:
	Net realized gains on investments		(70,607	)		4,220			(66,387	)
	Net impairment losses on investments		2,882			(265	)		2,617
	Total reclassifications to net income		(67,725	)		3,955			(63,770	)
	Other comprehensive income (loss)		5,842			(2,090	)		3,752
	Balance, end of period	$	174,703		$	(24,316	)	$	150,387
Schedule of amounts reclassified out of accumulated other comprehensive income	The following table sets forth the amounts reclassified out of accumulated other comprehensive income and the location of those amounts in the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
		September 30,						September 30,
		2013			2012			2013			2012
	Revenue:
	Net realized gains on investments	$	-		$	22,710		$	27,243		$	70,607
	Net impairment losses on investments		(65	)		(699	)		(2,002	)		(2,882	)
	Income tax expense	$	-		$	2,433		$	3,642		$	3,955

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information (Tables)	9 Months Ended
	Sep. 30, 2013
Condensed Consolidating Financial Information [Abstract]
Schedule of condensed financial statements	The following tables present the condensed consolidating financial information for Platinum Holdings, Platinum Finance and the non-guarantor subsidiaries of Platinum Holdings as of September 30, 2013 and December 31, 2012 and for the three and nine months ended September 30, 2013 and 2012 ($ in thousands):
	Condensed Consolidating Balance Sheet
	30-Sep-13
		Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
	ASSETS
	Total investments	$	-		$	126		$	2,011,493		$	-		$	2,011,619
	Investment in subsidiaries		1,667,006			680,845			574,649			(2,922,500	)		-
	Cash and cash equivalents		28,124			148,204			1,389,077			-			1,565,405
	Reinsurance assets		-			-			293,775			-			293,775
	Other assets		12,248			1,808			124,404			-			138,460
	Total assets	$	1,707,378		$	830,983		$	4,393,398		$	(2,922,500	)	$	4,009,259
	LIABILITIES AND SHAREHOLDERS' EQUITY
	Liabilities
	Reinsurance liabilities	$	-		$	-		$	1,963,712		$	-		$	1,963,712
	Debt obligations		-			250,000			-			-			250,000
	Other liabilities		8,448			6,334			81,835			-			96,617
	Total liabilities	$	8,448		$	256,334		$	2,045,547		$	-		$	2,310,329
	Shareholders' Equity
	Common shares	$	279		$	-		$	8,000		$	(8,000	)	$	279
	Additional paid-in capital		-			214,660			2,022,889			(2,237,549	)		-
	Accumulated other comprehensive income		57,390			20,252			77,638			(97,890	)		57,390
	Retained earnings		1,641,261			339,737			239,324			(579,061	)		1,641,261
	Total shareholders' equity	$	1,698,930		$	574,649		$	2,347,851		$	(2,922,500	)	$	1,698,930
	Total liabilities and shareholders' equity	$	1,707,378		$	830,983		$	4,393,398		$	(2,922,500	)	$	4,009,259
	(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
	Condensed Consolidating Balance Sheet
	31-Dec-12
		Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
	ASSETS
	Total investments	$	-		$	181		$	2,227,118		$	-		$	2,227,299
	Investment in subsidiaries		1,821,818			636,814			540,354			(2,998,986	)		-
	Cash and cash equivalents		70,604			152,122			1,497,669			-			1,720,395
	Reinsurance assets		-			-			277,279			-			277,279
	Other assets		8,997			2,884			96,449			-			108,330
	Total assets	$	1,901,419		$	792,001		$	4,638,869		$	(2,998,986	)	$	4,333,303
	LIABILITIES AND SHAREHOLDERS' EQUITY
	Liabilities
	Reinsurance liabilities	$	-		$	-		$	2,140,241		$	-		$	2,140,241
	Debt obligations		-			250,000			-			-			250,000
	Other liabilities		6,885			1,647			39,996			-			48,528
	Total liabilities	$	6,885		$	251,647		$	2,180,237		$	-		$	2,438,769
	Shareholders' Equity
	Common shares	$	327		$	-		$	8,000		$	(8,000	)	$	327
	Additional paid-in capital		209,897			213,736			2,021,045			(2,234,781	)		209,897
	Accumulated other comprehensive income		137,690			41,386			179,071			(220,457	)		137,690
	Retained earnings		1,546,620			285,232			250,516			(535,748	)		1,546,620
	Total shareholders' equity	$	1,894,534		$	540,354		$	2,458,632		$	(2,998,986	)	$	1,894,534
	Total liabilities and shareholders' equity	$	1,901,419		$	792,001		$	4,638,869		$	(2,998,986	)	$	4,333,303
	(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
	Condensed Consolidating Statement of Operations
	For the Three Months Ended September 30, 2013
		Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
	Revenue:
	Net premiums earned	$	-		$	-		$	135,360		$	-		$	135,360
	Net investment income (expense)		1			(43	)		17,800			-			17,758
	Net realized gains (losses) on investments		-			-			(306	)		-			(306	)
	Net impairment losses on investments		-			-			(65	)		-			(65	)
	Other income (expense)		1,149			-			277			-			1,426
	Total revenue		1,150			(43	)		153,066			-			154,173
	Expenses:
	Net losses and loss adjustment expenses		-			-			44,142			-			44,142
	Net acquisition expenses		-			-			30,675			-			30,675
	Operating expenses		6,626			37			14,009			-			20,672
	Net foreign currency exchange losses (gains)		-			-			487			-			487
Interest expense		-			4,782			-			-			4,782
Total expenses		6,626			4,819			89,313			-			100,758
Income (loss) before income taxes		(5,476	)		(4,862	)		63,753			-			53,415
Income tax expense (benefit)		-			(1,589	)		16,719			-			15,130
Income (loss) before equity in earnings of subsidiaries		(5,476	)		(3,273	)		47,034			-			38,285
Equity in earnings of subsidiaries		43,761			29,948			26,675			(100,384	)		-
Net income	$	38,285		$	26,675		$	73,709		$	(100,384	)	$	38,285
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Operations
For the Three Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Revenue:
Net premiums earned	$	-		$	-		$	138,588		$	-		$	138,588
Net investment income (expense)		2			(3	)		23,210			-			23,209
Net realized gains (losses) on investments		-			-			22,982			-			22,982
Net impairment losses on investments		-			-			(699	)		-			(699	)
Other income (expense)		1,400			1			(1,497	)		-			(96	)
Total revenue		1,402			(2	)		182,584			-			183,984
Expenses:
Net losses and loss adjustment expenses		-			-			45,117			-			45,117
Net acquisition expenses		-			-			26,168			-			26,168
Operating expenses		5,842			49			14,075			-			19,966
Net foreign currency exchange losses (gains)		-			-			541			-			541
Interest expense		-			4,775			-			-			4,775
Total expenses		5,842			4,824			85,901			-			96,567
Income (loss) before income taxes		(4,440	)		(4,826	)		96,683			-			87,417
Income tax expense (benefit)		-			(1,625	)		4,178			-			2,553
Income (loss) before equity in earnings of subsidiaries		(4,440	)		(3,201	)		92,505			-			84,864
Equity in earnings of subsidiaries		89,304			8,175			4,974			(102,453	)		-
Net income	$	84,864		$	4,974		$	97,479		$	(102,453	)	$	84,864
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Operations
For the Nine Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Revenue:
Net premiums earned	$	-		$	-		$	405,146		$	-		$	405,146
Net investment income (expense)		23			(73	)		54,160			-			54,110
Net realized gains on investments		-			-			24,698			-			24,698
Net impairment losses on investments		-			-			(2,002	)		-			(2,002	)
Other income (expense)		5,994			4			(3,495	)		-			2,503
Total revenue		6,017			(69	)		478,507			-			484,455
Expenses:
Net losses and loss adjustment expenses		-			-			120,807			-			120,807
Net acquisition expenses		-			-			91,207			-			91,207
Operating expenses		18,427			110			41,158			-			59,695
Net foreign currency exchange losses (gains)		-			-			(592	)		-			(592	)
Interest expense		-			14,341			-			-			14,341
Total expenses		18,427			14,451			252,580			-			285,458
Income (loss) before income taxes		(12,410	)		(14,520	)		225,927			-			198,997
Income tax expense (benefit)		-			(4,785	)		29,127			-			24,342
Income (loss) before equity in earnings of subsidiaries		(12,410	)		(9,735	)		196,800			-			174,655
Equity in earnings of subsidiaries		187,065			64,241			54,506			(305,812	)		-
Net income	$	174,655		$	54,506		$	251,306		$	(305,812	)	$	174,655
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Operations
For the Nine Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Revenue:
Net premiums earned	$	-		$	-		$	421,875		$	-		$	421,875
Net investment income (expense)		5			(10	)		77,921			-			77,916
Net realized gains on investments		-			-			70,299			-			70,299
Net impairment losses on investments		-			-			(2,882	)		-			(2,882	)
Other income (expense)		3,587			2			(4,355	)		-			(766	)
Total revenue		3,592			(8	)		562,858			-			566,442
Expenses:
Net losses and loss adjustment expenses		-			-			191,430			-			191,430
Net acquisition expenses		-			-			87,025			-			87,025
Operating expenses		16,617			182			39,846			-			56,645
Net foreign currency exchange losses (gains)		-			-			763			-			763
Interest expense		-			14,321			-			-			14,321
Total expenses		16,617			14,503			319,064			-			350,184
Income (loss) before income taxes		(13,025	)		(14,511	)		243,794			-			216,258
Income tax expense (benefit)		-			(4,890	)		15,465			-			10,575
Income (loss) before equity in earnings of subsidiaries		(13,025	)		(9,621	)		228,329			-			205,683
Equity in earnings of subsidiaries		218,708			40,116			30,495			(289,319	)		-
Net income	$	205,683		$	30,495		$	258,824		$	(289,319	)	$	205,683
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Three Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	38,285		$	26,675		$	73,709		$	(100,384	)	$	38,285
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			14			-			14
Change in net unrealized gains and losses on all other securities		-			-			(7,622	)		-			(7,622	)
Total change in net unrealized gains and losses		-			-			(7,608	)		-			(7,608	)
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			-			-			-
Net impairment losses on investments		-			-			65			-			65
Total reclassifications to net income		-			-			65			-			65
Other comprehensive income (loss) before income taxes		-			-			(7,543	)		-			(7,543	)
Income tax benefit (expense)		-			(1	)		567			-			566
Other comprehensive income (loss)		-			(1	)		(6,976	)		-			(6,977	)
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		(6,977	)		(1,049	)		(1,050	)		9,076			-
Comprehensive income	$	31,308		$	25,625		$	65,683		$	(91,308	)	$	31,308
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Three Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	84,864		$	4,974		$	97,479		$	(102,453	)	$	84,864
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			354			-			354
Change in net unrealized gains and losses on all other securities		-			(2	)		24,213			-			24,211
Total change in net unrealized gains and losses		-			(2	)		24,567			-			24,565
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			(22,710	)		-			(22,710	)
Net impairment losses on investments		-			-			699			-			699
Total reclassifications to net income		-			-			(22,011	)		-			(22,011	)
Other comprehensive income (loss) before income taxes		-			(2	)		2,556			-			2,554
Income tax benefit (expense)		-			1			(730	)		-			(729	)
Other comprehensive income (loss)		-			(1	)		1,826			-			1,825
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		1,825			1,356			1,355			(4,536	)		-
Comprehensive income	$	86,689		$	6,329		$	100,660		$	(106,989	)	$	86,689
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Nine Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	174,655		$	54,506		$	251,306		$	(305,812	)	$	174,655
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			(600	)		-			(600	)
Change in net unrealized gains and losses on all other securities		-			(2	)		(65,837	)		-			(65,839	)
Total change in net unrealized gains and losses		-			(2	)		(66,437	)		-			(66,439	)
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			(27,243	)		-			(27,243	)
Net impairment losses on investments		-			-			2,002			-			2,002
Total reclassifications to net income		-			-			(25,241	)		-			(25,241	)
Other comprehensive income (loss) before income taxes		-			(2	)		(91,678	)		-			(91,680	)
Income tax benefit (expense)		-			1			11,379			-			11,380
Other comprehensive income (loss)		-			(1	)		(80,299	)		-			(80,300	)
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		(80,300	)		(21,133	)		(21,134	)		122,567			-
Comprehensive income	$	94,355		$	33,372		$	149,873		$	(183,245	)	$	94,355
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
For the Nine Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries(1)			Consolidating Adjustments			Consolidated
Net income	$	205,683		$	30,495		$	258,824		$	(289,319	)	$	205,683
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded		-			-			263			-			263
Change in net unrealized gains and losses on all other securities		-			(3	)		73,307			-			73,304
Total change in net unrealized gains and losses		-			(3	)		73,570			-			73,567
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments		-			-			(70,607	)		-			(70,607	)
Net impairment losses on investments		-			-			2,882			-			2,882
Total reclassifications to net income		-			-			(67,725	)		-			(67,725	)
Other comprehensive income (loss) before income taxes		-			(3	)		5,845			-			5,842
Income tax benefit (expense)		-			2			(2,092	)		-			(2,090	)
Other comprehensive income (loss)		-			(1	)		3,753			-			3,752
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries		3,752			3,883			3,882			(11,517	)		-
Comprehensive income	$	209,435		$	34,377		$	266,459		$	(300,836	)	$	209,435
(1)        Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.
Condensed Consolidating Statement of Cash Flows
For the Nine Months Ended September 30, 2013
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net cash provided by (used in) operating activities	$	(8,724	)	$	(3,970	)	$	(481	)	$	(923	)	$	(14,098	)
Investing Activities:
Proceeds from the sales of:
Fixed maturity available-for-sale securities		-			-			203,571			-			203,571
Short-term investments		-			-			11,857			-			11,857
Proceeds from the maturities or paydowns of:
Fixed maturity available-for-sale securities		-			52			155,194			-			155,246
Short-term investments		-			-			209,240			-			209,240
Acquisitions of:
Fixed maturity available-for-sale securities		-			-			(291,006	)		-			(291,006	)
Short-term investments		-			-			(121,306	)		-			(121,306	)
Dividends from subsidiaries		262,500			-			-			(262,500	)		-
Acquisitions of furniture, equipment and other assets		(772	)		-			(5,416	)		-			(6,188	)
Net cash provided by (used in) investing activities		261,728			52			162,134			(262,500	)		161,414
Financing Activities:
Dividends paid to common shareholders		(7,181	)		-			(262,500	)		262,500			(7,181	)
Repurchase of common shares		(302,765	)		-			-			-			(302,765	)
Proceeds from share-based compensation, including income tax benefits		14,462			-			-			923			15,385
Net cash provided by (used in) financing activities		(295,484	)		-			(262,500	)		263,423			(294,561	)
Effect of foreign currency exchange rate changes on cash and cash equivalents		-			-			(7,745	)		-			(7,745	)
Net increase (decrease) in cash and cash equivalents		(42,480	)		(3,918	)		(108,592	)		-			(154,990	)
Cash and cash equivalents at beginning of period		70,604			152,122			1,497,669			-			1,720,395
Cash and cash equivalents at end of period	$	28,124		$	148,204		$	1,389,077		$	-		$	1,565,405
Condensed Consolidating Statement of Cash Flows
For the Nine Months Ended September 30, 2012
	Platinum Holdings			Platinum Finance			Non-guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net cash provided by (used in) operating activities	$	(7,874	)	$	(3,507	)	$	(7,588	)	$	-		$	(18,969	)
Investing Activities:
Proceeds from the sales of:
Fixed maturity available-for-sale securities		-			-			558,848			-			558,848
Short-term investments		-			-			36,581			-			36,581
Proceeds from the maturities or paydowns of:
Fixed maturity available-for-sale securities		-			63			213,440			-			213,503
Short-term investments		-			-			663,011			-			663,011
Acquisitions of:
Fixed maturity available-for-sale securities		-			-			(202,729	)		-			(202,729	)
Short-term investments		-			-			(266,723	)		-			(266,723	)
Dividends from subsidiaries		120,000			-			-			(120,000	)		-
Net cash provided by (used in) investing activities		120,000			63			1,002,428			(120,000	)		1,002,491
Financing Activities:
Dividends paid to common shareholders		(8,137	)		-			(120,000	)		120,000			(8,137	)
Repurchase of common shares		(109,633	)		-			-			-			(109,633	)
Proceeds from share-based compensation, including income tax benefits		2,554			-			-			-			2,554
Net cash provided by (used in) financing activities		(115,216	)		-			(120,000	)		120,000			(115,216	)
Effect of foreign currency exchange rate changes on cash and cash equivalents		-			-			1,863			-			1,863
Net increase (decrease) in cash and cash equivalents		(3,090	)		(3,444	)		876,703			-			870,169
Cash and cash equivalents at beginning of period		47,791			108,260			636,459			-			792,510
Cash and cash equivalents at end of period	$	44,701		$	104,816		$	1,513,162		$	-		$	1,662,679

Investments_Details

Investments (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	$1,767,085		$1,781,549
Gross unrealized gains	78,780		164,972
Gross unrealized losses	10,485		4,836
Fair value	1,835,380		1,941,685
Non-credit portion of OTTI	788	[1]	3,205	[1]
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than twelve months	339,684		30,189
Twelve months or more	15,344		24,696
Total unrealized losses	355,028		54,885
Continuous Unrealized Loss Position, Unrealized Loss [ Abstract]
Less than twelve months	8,994		290
Twelve months or more	1,491		4,546
Total unrealized losses	10,485		4,836
US Government [Member]
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	4,579		4,632
Gross unrealized gains	230		312
Gross unrealized losses	0		0
Fair value	4,809		4,944
Non-credit portion of OTTI	0	[1]	0	[1]
Municipal Bonds [Member]
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	1,217,511		1,080,273
Gross unrealized gains	62,751		129,735
Gross unrealized losses	5,453		74
Fair value	1,274,809		1,209,934
Non-credit portion of OTTI	0	[1]	0	[1]
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than twelve months	207,187		18,878
Twelve months or more	0		0
Total unrealized losses	207,187		18,878
Continuous Unrealized Loss Position, Unrealized Loss [ Abstract]
Less than twelve months	5,453		74
Twelve months or more	0		0
Total unrealized losses	5,453		74
Non-US Governments [Member]
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	39,971		49,978
Gross unrealized gains	541		999
Gross unrealized losses	0		0
Fair value	40,512		50,977
Non-credit portion of OTTI	0	[1]	0	[1]
Corporate Bonds [Member]
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	226,835		279,981
Gross unrealized gains	7,023		21,109
Gross unrealized losses	3,016		182
Fair value	230,842		300,908
Non-credit portion of OTTI	0	[1]	0	[1]
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than twelve months	85,865		4,450
Twelve months or more	0		6,039
Total unrealized losses	85,865		10,489
Continuous Unrealized Loss Position, Unrealized Loss [ Abstract]
Less than twelve months	3,016		41
Twelve months or more	0		141
Total unrealized losses	3,016		182
Commercial Mortgage-Backed Securities [Member]
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	83,270		127,148
Gross unrealized gains	5,126		8,807
Gross unrealized losses	292		429
Fair value	88,104		135,526
Non-credit portion of OTTI	0	[1]	264	[1]
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than twelve months	4,463		6,758
Twelve months or more	0		762
Total unrealized losses	4,463		7,520
Continuous Unrealized Loss Position, Unrealized Loss [ Abstract]
Less than twelve months	292		165
Twelve months or more	0		264
Total unrealized losses	292		429
Residential Mortgage-Backed Securities [Member]
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	178,662		222,331
Gross unrealized gains	1,500		2,584
Gross unrealized losses	1,367		3,293
Fair value	178,795		221,622
Non-credit portion of OTTI	502	[1]	2,083	[1]
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than twelve months	28,640		39
Twelve months or more	14,572		17,096
Total unrealized losses	43,212		17,135
Continuous Unrealized Loss Position, Unrealized Loss [ Abstract]
Less than twelve months	162		9
Twelve months or more	1,205		3,284
Total unrealized losses	1,367		3,293
Asset-Backed Securities [Member]
Amortized Cost, Gross Unrealized Gains, Losses, FV and OTTI of AFS Securities [Abstract]
Amortized cost	16,257		17,206
Gross unrealized gains	1,609		1,426
Gross unrealized losses	357		858
Fair value	17,509		17,774
Non-credit portion of OTTI	286	[1]	858	[1]
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than twelve months	13,529		64
Twelve months or more	772		799
Total unrealized losses	14,301		863
Continuous Unrealized Loss Position, Unrealized Loss [ Abstract]
Less than twelve months	71		1
Twelve months or more	286		857
Total unrealized losses	$357		$858
[1]	The non-credit portion of other than temporary impairments ("OTTI") represents the amount of unrealized losses on impaired securities that were not recorded in the consolidated statements of operations as of the reporting date. These unrealized losses are included in gross unrealized losses as of September 30, 2013 and December 31, 2012.

Investments_Trading_Securities

Investments, Trading Securities (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fixed Maturity Trading Securities [Abstract]
Fair Value	$102,604	$112,813
Non-US Governments [Member]
Fixed Maturity Trading Securities [Abstract]
Fair Value	$102,604	$112,813

Investments_Maturities_of_Avai

Investments, Maturities of Available-for-sale and Trading Securities (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Amortized Cost [Abstract]
Due in one year or less	$41,124
Due from one to five years	475,473
Due from five to ten years	658,273
Due in ten or more years	410,416
Mortgage-backed and asset-backed securities	278,189
Total	1,863,475
Fair Value [Abstract]
Due in one year or less	41,612
Due from one to five years	495,931
Due from five to ten years	681,902
Due in ten or more years	434,131
Mortgage-backed and asset-backed securities	284,408
Total	$1,937,984

Investments_Short_Term_Investm

Investments, Short Term Investments (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Schedule Of Short Term Investments [Line Items]
Short-term investment fair value	$73,635,000		$172,801,000
Short-Term Investments [Abstract]
Acquisition of non-USD short-term investments	121,300,000	204,300,000
Proceeds from sales of non-USD short-term investments	11,900,000	36,600,000
Proceeds from maturities of non-USD short-term investments	160,000,000	242,000,000
US Government [Member]
Schedule Of Short Term Investments [Line Items]
Short-term investment fair value	0		49,186,000
Non-US Governments [Member]
Schedule Of Short Term Investments [Line Items]
Short-term investment fair value	$73,635,000		$123,615,000

Investments_Other_Than_Tempora

Investments, Other Than Temporary Impairments (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net impairment losses on investments [Abstract]
Net impairment losses on investments	$65,000	$699,000	$2,002,000	$2,882,000
Largest unrealized loss on single commercial mortgage-backed securities	300,000		300,000
Amortized cost of single commercial mortgage-backed security with largest unrealized loss	4,800,000		4,800,000
Largest unrealized loss on single non-agency residential mortgage-backed securities	600,000		600,000
Amortized cost of single non-agency residential mortgage-backed security with largest unrealized loss	4,100,000		4,100,000
Largest unrealized loss on single sub-prime asset-backed securities	300,000		300,000
Amortized cost of single sub-prime asset-backed security with largest unrealized loss	600,000		600,000
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	35,762,000	57,874,000	40,219,000	61,841,000
Credit losses on securities not previously impaired	0	42,000	0	42,000
Credit losses on securities previously impaired	65,000	657,000	2,002,000	2,840,000
Reduction for paydowns and securities sold	-2,956,000	-3,447,000	-9,094,000	-9,168,000
Reduction for increases in cash flows expected to be collected	-195,000	-309,000	-451,000	-738,000
Balance, end of period	32,676,000	54,817,000	32,676,000	54,817,000
Cumulative Credit Losses [Abstract]
Cumulative credit losses recorded on commercial mortgage-backed securities	1,200,000		1,200,000
Number of commercial mortgage-backed securities comprising cumulative credit losses	2		2
Percentage of mortgages backing CMBS that were past due	3.40%		3.40%
Number of days without payment for mortgage to be considered past due	90		90
Percentage of CMBS mortgages included in cumulative losses	1.00%		1.00%
Percentage of remaining credit support allocated for CMBS mortgages with incurred losses	4.60%		4.60%
Cumulative credit losses recorded on non-agency residential mortgage-backed securities and sub-prime asset-backed securities	31,500,000		31,500,000
Number of non-agency RMBS and sub-prime ABS securities comprising cumulative credit losses	17		17
Percentage of mortgages backing non-agency RMBS and sub-prime ABS securities that were past due	16.00%		16.00%
Percentage of non-agency RMBS and sub-prime ABS mortgages included in cumulative losses	7.90%		7.90%
Percentage of remaining credit support for non-agency RMBS and sub-prime ABS mortgages which incurred losses	2.90%		2.90%
Commercial Mortgage-Backed Securities [Member]
Net impairment losses on investments [Abstract]
Net impairment losses on investments	0	0	0	30,000
Non-Agency Residential Mortgage-Backed Securities [Member]
Net impairment losses on investments [Abstract]
Net impairment losses on investments	28,000	693,000	1,439,000	2,839,000
Sub-Prime Asset-Backed Securities [Member]
Net impairment losses on investments [Abstract]
Net impairment losses on investments	$37,000	$6,000	$563,000	$13,000

Investments_Investment_Income_

Investments, Investment Income and Net Realized Gains Losses (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Investment Income [Abstract]
Investment income	$18,660	$24,253	$57,149	$81,188
Investment expenses	-902	-1,044	-3,039	-3,272
Net investment income (expense)	17,758	23,209	54,110	77,916
Net Realized Gain (Loss) on Investments [Abstract]
Gross realized gains on the sale of investments	0	22,979	27,258	70,920
Gross realized losses on the sale of investments	0	0	-15	-1
Net realized gains on the sale of investments	0	22,979	27,243	70,919
Fair value adjustments on trading securities	-306	3	-2,545	-620
Net realized gains (losses) on investments	-306	22,982	24,698	70,299
Fixed Maturity Securities [Member]
Net Investment Income [Abstract]
Investment income	16,815	22,022	51,428	73,892
Short-Term Investment And Cash And Cash Equivalents [Member]
Net Investment Income [Abstract]
Investment income	1,123	1,547	3,346	5,358
Funds Held By Ceding Companies [Member]
Net Investment Income [Abstract]
Investment income	$722	$684	$2,375	$1,938

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Investments:
U.S. Government	$4,809,000		$4,809,000		$4,944,000
Municipal bonds	1,274,809,000		1,274,809,000		1,209,934,000
Non-U.S. governments	143,116,000		143,116,000		163,790,000
Corporate bonds	230,842,000		230,842,000		300,908,000
Commercial mortgage-backed securities	88,104,000		88,104,000		135,526,000
Residential mortgage-backed securities	178,795,000		178,795,000		221,622,000
Asset-backed securities	17,509,000		17,509,000		17,774,000
Short-term investments	73,635,000		73,635,000		172,801,000
Total investments	2,011,619,000		2,011,619,000		2,227,299,000
Reinsurance deposit assets	78,179,000		78,179,000		50,693,000
Total	2,089,798,000		2,089,798,000		2,277,992,000
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Balance, beginning of period	82,725,000	9,027,000	57,627,000	10,013,000	10,013,000
Purchases			25,000,000
Sales, maturities and paydowns	-269,000	-935,000	-464,000	-1,669,000
Total increase (decrease) in fair value included in earnings	1,231,000	0	2,486,000	0
Total net unrealized gains (losses) included in other comprehensive income (loss)	254,000	1,759,000	1,191,000	1,508,000
Transfers into Level 3	1,378,000	8,739,000	8,033,000	10,992,000
Transfers out of Level 3	-4,065,000	-4,314,000	-12,619,000	-6,568,000
Balance, end of period	81,254,000	14,276,000	81,254,000	14,276,000	57,627,000
Total increase (decrease) in fair value of the financial assets included in earnings for the period	1,231,000	0	2,486,000	0
Deposit Assets [Abstract]
Reinsurance deposit asset contract terms			The terms of these agreements provide for a book yield ranging from a minimum of 3.0% to a maximum of 6.5% accumulating over the estimated contract periods.
Purchase cost of reinsurance deposit assets			75,000,000
Estimated contract period remaining	1,282 days		1,282 days		1,350 days
Credit spread above the risk-free rate			1.84%		2.47%
Net losses and LAE ceded inception-to-date	0		0		0
Debt Obligations [Abstract]
Debt obligations at carrying value	250,000,000		250,000,000		250,000,000
Debt obligations at fair value	273,000,000		273,000,000		278,500,000
Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Balance, beginning of period	0	0	524,000	0	0
Purchases			0
Sales, maturities and paydowns	0	0	0	0
Total increase (decrease) in fair value included in earnings	0	0	0	0
Total net unrealized gains (losses) included in other comprehensive income (loss)	0	0	487,000	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	-1,011,000	0
Balance, end of period	0	0	0	0
Total increase (decrease) in fair value of the financial assets included in earnings for the period	0	0	0	0
Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Balance, beginning of period	4,520,000	7,461,000	5,374,000	8,146,000	8,146,000
Purchases			0
Sales, maturities and paydowns	-269,000	-935,000	-435,000	-1,669,000
Total increase (decrease) in fair value included in earnings	0	0	0	0
Total net unrealized gains (losses) included in other comprehensive income (loss)	329,000	1,789,000	750,000	1,839,000
Transfers into Level 3	0	3,807,000	4,049,000	6,060,000
Transfers out of Level 3	-4,065,000	-3,915,000	-9,223,000	-6,169,000
Balance, end of period	515,000	8,207,000	515,000	8,207,000
Total increase (decrease) in fair value of the financial assets included in earnings for the period	0	0	0	0
Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Balance, beginning of period	1,257,000	1,566,000	1,036,000	1,867,000	1,867,000
Purchases			0
Sales, maturities and paydowns	0	0	-29,000	0
Total increase (decrease) in fair value included in earnings	0	0	0	0
Total net unrealized gains (losses) included in other comprehensive income (loss)	-75,000	-30,000	-46,000	-331,000
Transfers into Level 3	1,378,000	4,932,000	3,984,000	4,932,000
Transfers out of Level 3	0	-399,000	-2,385,000	-399,000
Balance, end of period	2,560,000	6,069,000	2,560,000	6,069,000
Total increase (decrease) in fair value of the financial assets included in earnings for the period	0	0	0	0
Reinsurance Deposit Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Balance, beginning of period	76,948,000	0	50,693,000	0	0
Purchases			25,000,000
Sales, maturities and paydowns	0	0	0	0
Total increase (decrease) in fair value included in earnings	1,231,000	0	2,486,000	0
Total net unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	78,179,000	0	78,179,000	0
Total increase (decrease) in fair value of the financial assets included in earnings for the period	1,231,000	0	2,486,000	0
Fair Value, Measurements, Recurring [Member] | Fair Value Measurement Using Level 1 [Member]
Investments:
U.S. Government	4,809,000		4,809,000		4,944,000
Municipal bonds	0		0		0
Non-U.S. governments	54,437,000		54,437,000		56,422,000
Corporate bonds	0		0		0
Commercial mortgage-backed securities	0		0		0
Residential mortgage-backed securities	0		0		0
Asset-backed securities	0		0		0
Short-term investments	0		0		0
Total investments	59,246,000		59,246,000		61,366,000
Reinsurance deposit assets	0		0		0
Total	59,246,000		59,246,000		61,366,000
Fair Value, Measurements, Recurring [Member] | Fair Value Measurement Using Level 2 [Member]
Investments:
U.S. Government	0		0		0
Municipal bonds	1,274,809,000		1,274,809,000		1,209,934,000
Non-U.S. governments	88,679,000		88,679,000		107,368,000
Corporate bonds	230,842,000		230,842,000		300,908,000
Commercial mortgage-backed securities	88,104,000		88,104,000		135,002,000
Residential mortgage-backed securities	178,280,000		178,280,000		216,248,000
Asset-backed securities	14,949,000		14,949,000		16,738,000
Short-term investments	73,635,000		73,635,000		172,801,000
Total investments	1,949,298,000		1,949,298,000		2,158,999,000
Reinsurance deposit assets	0		0		0
Total	1,949,298,000		1,949,298,000		2,158,999,000
Fair Value, Measurements, Recurring [Member] | Fair Value Measurement Using Level 3 [Member]
Investments:
U.S. Government	0		0		0
Municipal bonds	0		0		0
Non-U.S. governments	0		0		0
Corporate bonds	0		0		0
Commercial mortgage-backed securities	0		0		524,000
Residential mortgage-backed securities	515,000		515,000		5,374,000
Asset-backed securities	2,560,000		2,560,000		1,036,000
Short-term investments	0		0		0
Total investments	3,075,000		3,075,000		6,934,000
Reinsurance deposit assets	78,179,000		78,179,000		50,693,000
Total	$81,254,000		$81,254,000		$57,627,000

Credit_Facilities_Details

Credit Facilities (Details) (USD $)	9 Months Ended					3 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
		Syndicated Credit Facility [Member]	Syndicated Credit Facility [Member]	Syndicated Credit Facility [Member]	Other LOC Facilities [Member]	Uncommitted LOC Facilities [Member]
			Secured Credit Facility [Member]	Unsecured Credit Facility [Member]
Line of Credit Facility [Line Items]
Letters of credit, affiliated borrower	reinsurance subsidiaries
Letters of credit, covenant compliance	we were in compliance with covenants under our credit facilities
Letters of credit, maximum borrowing capacity	$415,405,000	$300,000,000	$200,000,000	$100,000,000	$115,405,000
Letters of credit, amount outstanding	124,473,000	80,405,000	80,405,000	0	44,068,000
Collateral, cash and cash equivalents	160,673,000	93,356,000	93,356,000	0	67,317,000
Letters of credit, borrowing capacity increase						50,000,000
Letters of credit, remaining borrowing capacity available						259,600,000
Amount of additional borrowing allowed with lender approval	$175,000,000

Income_Taxes_Details

Income Taxes (Details) (United States [Member], USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
United States [Member]
Income Taxes [Line Items]
Income tax examination, refund adjustment from settlement with taxing authority	$6
Income tax examination, accrued interest portion	$1.30
Income tax returns that remain open to examination	2010 and later

Share_Repurchases_Details

Share Repurchases (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Share Repurchases [Abstract]
Share repurchase authorization description		Our Board of Directors has authorized the repurchase of our common shares through a share repurchase program. Since the program was established, our Board of Directors has approved increases in the repurchase program from time to time, most recently on July 24, 2013, to result in authority as of such date to repurchase up to a total of $250.0 million of our common shares.
Amount authorized to repurchase common stock shares		$250,000,000
Number of common shares repurchased and retired during the period (in shares)	1,353,682	5,351,343
Aggregate amount paid for common shares repurchased and retired during the period	78,500,000	302,765,000	109,633,000
Weighted average cost per share for shares repurchased and retired (in dollars per share)	$58.01	$56.58
Stock repurchase program remaining authorized repurchase amount		$171,500,000

Statutory_Regulations_and_Divi2

Statutory Regulations and Dividend Restrictions (Details) (USD $)	9 Months Ended		1 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Oct. 23, 2013	Oct. 23, 2013	Sep. 30, 2013	Sep. 30, 2013
			Platinum Holdings [Member]	Platinum Bermuda [Member]	Platinum Bermuda [Member]	Platinum United States [Member]
Statutory Accounting Practices [Line Items]
Maximum amount available for payment of dividends without prior regulatory approval	$349,122				$318,343	$30,779
Remaining amount available for payment of dividends or other distributions by reinsurance subsidiaries without regulatory approval	86,622				55,843	30,779
Dividends paid during period	262,500			55,800	262,500	0
Dividends received during period	$0	$0	$55,800

Operating_Segment_Information_1

Operating Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Net premiums written	$137,898,000	$145,979,000	$419,033,000	$431,099,000
Net premiums earned	135,360,000	138,588,000	405,146,000	421,875,000
Net losses and loss adjustment expenses	44,142,000	45,117,000	120,807,000	191,430,000
Net acquisition expenses	30,675,000	26,168,000	91,207,000	87,025,000
Other underwriting expenses	13,816,000	13,612,000	40,615,000	39,020,000
Segment underwriting income (loss)	46,727,000	53,691,000	152,517,000	104,400,000
Reconciliation of operating profit (loss) from segments to consolidated:
Net investment income (expense)	17,758,000	23,209,000	54,110,000	77,916,000
Net realized gains (losses) on investments	-306,000	22,982,000	24,698,000	70,299,000
Net impairment losses on investments	-65,000	-699,000	-2,002,000	-2,882,000
Other income (expense)	1,426,000	-96,000	2,503,000	-766,000
Corporate expenses not allocated to segments	-6,856,000	-6,354,000	-19,080,000	-17,625,000
Net foreign currency exchange (losses) gains	-487,000	-541,000	592,000	-763,000
Interest expense	-4,782,000	-4,775,000	-14,341,000	-14,321,000
Income (loss) before income taxes	53,415,000	87,417,000	198,997,000	216,258,000
Underwriting Ratios:
Net loss and loss adjustment expense	32.60%	32.60%	29.80%	45.40%
Net acquisition expense	22.70%	18.90%	22.50%	20.60%
Other underwriting expense	10.20%	9.80%	10.00%	9.20%
Combined	65.50%	61.30%	62.30%	75.20%
Property and Marine [Member]
Segment Reporting Information [Line Items]
Net premiums written	59,169,000	64,876,000	175,946,000	194,724,000
Net premiums earned	55,127,000	61,900,000	165,811,000	186,066,000
Net losses and loss adjustment expenses	28,339,000	26,790,000	35,426,000	85,380,000
Net acquisition expenses	9,699,000	7,078,000	27,624,000	25,034,000
Other underwriting expenses	7,747,000	7,661,000	22,493,000	21,950,000
Segment underwriting income (loss)	9,342,000	20,371,000	80,268,000	53,702,000
Underwriting Ratios:
Net loss and loss adjustment expense	51.40%	43.30%	21.40%	45.90%
Net acquisition expense	17.60%	11.40%	16.70%	13.50%
Other underwriting expense	14.10%	12.40%	13.60%	11.80%
Combined	83.10%	67.10%	51.70%	71.20%
Casualty [Member]
Segment Reporting Information [Line Items]
Net premiums written	69,992,000	72,358,000	220,547,000	219,436,000
Net premiums earned	72,543,000	70,326,000	218,967,000	221,838,000
Net losses and loss adjustment expenses	10,242,000	14,358,000	75,243,000	101,245,000
Net acquisition expenses	19,067,000	16,710,000	53,384,000	52,572,000
Other underwriting expenses	5,727,000	5,662,000	17,120,000	16,323,000
Segment underwriting income (loss)	37,507,000	33,596,000	73,220,000	51,698,000
Underwriting Ratios:
Net loss and loss adjustment expense	14.10%	20.40%	34.40%	45.60%
Net acquisition expense	26.30%	23.80%	24.40%	23.70%
Other underwriting expense	7.90%	8.10%	7.80%	7.40%
Combined	48.30%	52.30%	66.60%	76.70%
Finite Risk [Member]
Segment Reporting Information [Line Items]
Net premiums written	8,737,000	8,745,000	22,540,000	16,939,000
Net premiums earned	7,690,000	6,362,000	20,368,000	13,971,000
Net losses and loss adjustment expenses	5,561,000	3,969,000	10,138,000	4,805,000
Net acquisition expenses	1,909,000	2,380,000	10,199,000	9,419,000
Other underwriting expenses	342,000	289,000	1,002,000	747,000
Segment underwriting income (loss)	($122,000)	($276,000)	($971,000)	($1,000,000)
Underwriting Ratios:
Net loss and loss adjustment expense	72.30%	62.40%	49.80%	34.40%
Net acquisition expense	24.80%	37.40%	50.10%	67.40%
Other underwriting expense	4.40%	4.50%	4.90%	5.30%
Combined	101.50%	104.30%	104.80%	107.10%

Earnings_Loss_Per_Common_Share2

Earnings (Loss) Per Common Share (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Earnings (Loss) - Basic and Diluted [Abstract]
Net income (loss) attributable to common shareholders	$38,285		$84,864		$174,655		$205,683
Portion allocated to participating common shareholders	-26	[1]	-234	[1]	-301	[1]	-740	[1]
Net income allocated to common shareholders	$38,259		$84,630		$174,354		$204,943
Common Shares - Basic [Abstract]
Weighted average common shares outstanding (in shares)	28,655		32,996		30,519		34,063
Common Shares - Diluted [Abstract]
Weighted average common shares outstanding (in shares)	28,655		32,996		30,519		34,063
Effect of Dilutive Securities [Abstract]
Common share options (in shares)	131		179		173		154
Restricted share units (in shares)	279		97		257		69
Adjusted weighted average common shares outstanding (in shares)	29,065		33,272		30,949		34,286
Earnings (Loss) Per Common Share [Abstract]
Basic earnings (loss) per common share (in dollars per share)	$1.34		$2.56		$5.71		$6.02
Diluted earnings (loss) per common share (in dollars per share)	$1.32		$2.54		$5.63		$5.98
[1]	Represents earnings attributable to holders of unvested restricted shares issued under the Company's share incentive plans that are considered to be participating securities. In July 2013, the remaining outstanding restricted shares vested and therefore there were no unvested restricted shares as of September 30, 2013.

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated other comprehensive income (loss), pre-tax [Abstract]
Balance, beginning of period	$75,838	$172,149	$159,975	$168,861
Other comprehensive income (loss) on available-for-sale securities before reclassifications, pre-tax [Abstract]
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	14	354	-600	263
Change in net unrealized gains and losses on all other securities	-7,622	24,211	-65,839	73,304
Total change in net unrealized gains and losses	-7,608	24,565	-66,439	73,567
Reclassifications to net income on available-for-sale securities, pre-tax [Abstract]
Net realized gains on investments	0	-22,710	-27,243	-70,607
Net impairment losses on investments	65	699	2,002	2,882
Total reclassifications to net income	65	-22,011	-25,241	-67,725
Other comprehensive income (loss)	-7,543	2,554	-91,680	5,842
Balance, end of period	68,295	174,703	68,295	174,703
Accumulated other comprehensive income (loss), tax [Abstract]
Balance, beginning of period	-11,471	-23,587	-22,285	-22,226
Other comprehensive income (loss) on available-for-sale securities before reclassifications, tax [Abstract]
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	0	19	11	79
Change in net unrealized gains and losses on all other securities	566	-3,181	7,727	-6,124
Total change in net unrealized gains and losses	566	-3,162	7,738	-6,045
Reclassifications to net income on available-for-sale securities, tax [Abstract]
Net realized gains on investments	0	2,466	3,675	4,220
Net impairment losses on investments	0	-33	-33	-265
Total reclassifications to net income	0	2,433	3,642	3,955
Other comprehensive income (loss)	566	-729	11,380	-2,090
Balance, end of period	-10,905	-24,316	-10,905	-24,316
Accumulated other comprehensive income, net of tax [Abstract]
Balance, beginning of period	64,367	148,562	137,690	146,635
Other comprehensive income (loss) on available-for-sale securities before reclassifications, net of tax [Abstract]
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	14	373	-589	342
Change in net unrealized gains and losses on all other securities	-7,056	21,030	-58,112	67,180
Total change in net unrealized gains and losses	-7,042	21,403	-58,701	67,522
Reclassifications to net income on available-for-sale securities, net of tax [Abstract]
Net realized gains on investments	0	-20,244	-23,568	-66,387
Net impairment losses on investments	65	666	1,969	2,617
Total reclassifications to net income	65	-19,578	-21,599	-63,770
Other comprehensive income (loss)	-6,977	1,825	-80,300	3,752
Balance, end of period	57,390	150,387	57,390	150,387
Reclassification out of accumulated other comprehensive income [Abstract]
Net realized gains on investments	0	22,710	27,243	70,607
Net impairment losses on investments	-65	-699	-2,002	-2,882
Income tax expense	$0	$2,433	$3,642	$3,955

Commitments_and_Contingencies_

Commitments and Contingencies (Details)	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies [Abstract]
Description of operating lease commitments	Our contractual obligations for these operating leases are $1.1 million annually beginning August 27, 2013, for a total of $10.8 million for the ten-year lease term.

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Jun. 30, 2013	Dec. 31, 2012		Jun. 30, 2012	Dec. 31, 2011
ASSETS
Total investments	$2,011,619,000				$2,011,619,000					$2,227,299,000
Investment in subsidiaries	0				0					0
Cash and cash equivalents	1,565,405,000		1,662,679,000		1,565,405,000		1,662,679,000
Reinsurance assets	293,775,000				293,775,000					277,279,000
Other assets	138,460,000				138,460,000					108,330,000
Total assets	4,009,259,000				4,009,259,000					4,333,303,000
Liabilities
Reinsurance liabilities	1,963,712,000				1,963,712,000					2,140,241,000
Debt obligations	250,000,000				250,000,000					250,000,000
Other liabilities	96,617,000				96,617,000					48,528,000
Total liabilities	2,310,329,000				2,310,329,000					2,438,769,000
Shareholders' Equity
Common shares	279,000				279,000					327,000
Additional paid-in capital	0				0					209,897,000
Accumulated other comprehensive income	57,390,000		150,387,000		57,390,000		150,387,000		64,367,000	137,690,000		148,562,000	146,635,000
Retained earnings	1,641,261,000				1,641,261,000					1,546,620,000
Total shareholders' equity	1,698,930,000		1,789,946,000		1,698,930,000		1,789,946,000			1,894,534,000
Total liabilities and shareholders' equity	4,009,259,000				4,009,259,000					4,333,303,000
Revenue:
Net premiums earned	135,360,000		138,588,000		405,146,000		421,875,000
Net investment income (expense)	17,758,000		23,209,000		54,110,000		77,916,000
Net realized gains (losses) on investments	-306,000		22,982,000		24,698,000		70,299,000
Net impairment losses on investments	-65,000		-699,000		-2,002,000		-2,882,000
Other income (expense)	1,426,000		-96,000		2,503,000		-766,000
Total revenue	154,173,000		183,984,000		484,455,000		566,442,000
Expenses:
Net losses and loss adjustment expenses	44,142,000		45,117,000		120,807,000		191,430,000
Net acquisition expenses	30,675,000		26,168,000		91,207,000		87,025,000
Operating expenses	20,672,000		19,966,000		59,695,000		56,645,000
Net foreign currency exchange losses (gains)	487,000		541,000		-592,000		763,000
Interest expense	4,782,000		4,775,000		14,341,000		14,321,000
Total expenses	100,758,000		96,567,000		285,458,000		350,184,000
Income (loss) before income taxes	53,415,000		87,417,000		198,997,000		216,258,000
Income tax expense (benefit)	15,130,000		2,553,000		24,342,000		10,575,000
Income (loss) before equity in earnings of subsidiaries	38,285,000		84,864,000		174,655,000		205,683,000
Equity in earnings of subsidiaries	0		0		0		0
Net income (loss)	38,285,000		84,864,000		174,655,000		205,683,000
Comprehensive Income (Loss) [Abstract]
Net income (loss)	38,285,000		84,864,000		174,655,000		205,683,000
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	14,000		354,000		-600,000		263,000
Change in net unrealized gains and losses on all other securities	-7,622,000		24,211,000		-65,839,000		73,304,000
Total change in net unrealized gains and losses	-7,608,000		24,565,000		-66,439,000		73,567,000
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments	0		-22,710,000		-27,243,000		-70,607,000
Net impairment losses on investments	65,000		699,000		2,002,000		2,882,000
Total reclassifications to net income	65,000		-22,011,000		-25,241,000		-67,725,000
Other comprehensive income (loss) before income taxes	-7,543,000		2,554,000		-91,680,000		5,842,000
Income tax benefit (expense)	566,000		-729,000		11,380,000		-2,090,000
Other comprehensive income (loss)	-6,977,000		1,825,000		-80,300,000		3,752,000
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries	0		0		0		0
Comprehensive income (loss)	31,308,000		86,689,000		94,355,000		209,435,000
Net cash provided by (used in) operating activities					-14,098,000		-18,969,000
Proceeds from the sales of:
Fixed maturity available-for-sale securities					203,571,000		558,848,000
Short-term investments					11,857,000		36,581,000
Proceeds from maturities or paydowns of:
Fixed maturity available-for-sale securities					155,246,000		213,503,000
Short-term investments					209,240,000		663,011,000
Acquisitions of:
Fixed maturity available-for-sale securities					-291,006,000		-202,729,000
Short-term investments					-121,306,000		-266,723,000
Dividends from subsidiaries					0		0
Acquisitions of furniture, equipment and other assets					-6,188,000		0
Net cash provided by (used in) investing activities					161,414,000		1,002,491,000
Financing Activities:
Dividends paid to common shareholders					-7,181,000		-8,137,000
Repurchase of common shares	-78,500,000				-302,765,000		-109,633,000
Proceeds from share-based compensation, including income tax benefits					15,385,000		2,554,000
Net cash provided by (used in) financing activities					-294,561,000		-115,216,000
Effect of foreign currency exchange rate changes on cash and cash equivalents					-7,745,000		1,863,000
Net increase (decrease) in cash and cash equivalents					-154,990,000		870,169,000
Cash and cash equivalents at beginning of period					1,720,395,000		792,510,000
Cash and cash equivalents at end of period	1,565,405,000		1,662,679,000		1,565,405,000		1,662,679,000
Platinum Holdings [Member]
Condensed Financial Statements, Captions [Line Items]
Amount guaranteed by Platinum Holdings	250,000,000				250,000,000
ASSETS
Total investments	0				0					0
Investment in subsidiaries	1,667,006,000				1,667,006,000					1,821,818,000
Cash and cash equivalents	28,124,000		44,701,000		28,124,000		44,701,000
Reinsurance assets	0				0					0
Other assets	12,248,000				12,248,000					8,997,000
Total assets	1,707,378,000				1,707,378,000					1,901,419,000
Liabilities
Reinsurance liabilities	0				0					0
Debt obligations	0				0					0
Other liabilities	8,448,000				8,448,000					6,885,000
Total liabilities	8,448,000				8,448,000					6,885,000
Shareholders' Equity
Common shares	279,000				279,000					327,000
Additional paid-in capital	0				0					209,897,000
Accumulated other comprehensive income	57,390,000				57,390,000					137,690,000
Retained earnings	1,641,261,000				1,641,261,000					1,546,620,000
Total shareholders' equity	1,698,930,000				1,698,930,000					1,894,534,000
Total liabilities and shareholders' equity	1,707,378,000				1,707,378,000					1,901,419,000
Revenue:
Net premiums earned	0		0		0		0
Net investment income (expense)	1,000		2,000		23,000		5,000
Net realized gains (losses) on investments	0		0		0		0
Net impairment losses on investments	0		0		0		0
Other income (expense)	1,149,000		1,400,000		5,994,000		3,587,000
Total revenue	1,150,000		1,402,000		6,017,000		3,592,000
Expenses:
Net losses and loss adjustment expenses	0		0		0		0
Net acquisition expenses	0		0		0		0
Operating expenses	6,626,000		5,842,000		18,427,000		16,617,000
Net foreign currency exchange losses (gains)	0		0		0		0
Interest expense	0		0		0		0
Total expenses	6,626,000		5,842,000		18,427,000		16,617,000
Income (loss) before income taxes	-5,476,000		-4,440,000		-12,410,000		-13,025,000
Income tax expense (benefit)	0		0		0		0
Income (loss) before equity in earnings of subsidiaries	-5,476,000		-4,440,000		-12,410,000		-13,025,000
Equity in earnings of subsidiaries	43,761,000		89,304,000		187,065,000		218,708,000
Net income (loss)	38,285,000		84,864,000		174,655,000		205,683,000
Comprehensive Income (Loss) [Abstract]
Net income (loss)	38,285,000		84,864,000		174,655,000		205,683,000
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	0		0		0		0
Change in net unrealized gains and losses on all other securities	0		0		0		0
Total change in net unrealized gains and losses	0		0		0		0
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments	0		0		0		0
Net impairment losses on investments	0		0		0		0
Total reclassifications to net income	0		0		0		0
Other comprehensive income (loss) before income taxes	0		0		0		0
Income tax benefit (expense)	0		0		0		0
Other comprehensive income (loss)	0		0		0		0
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries	-6,977,000		1,825,000		-80,300,000		3,752,000
Comprehensive income (loss)	31,308,000		86,689,000		94,355,000		209,435,000
Net cash provided by (used in) operating activities					-8,724,000		-7,874,000
Proceeds from the sales of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Proceeds from maturities or paydowns of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Acquisitions of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Dividends from subsidiaries					262,500,000		120,000,000
Acquisitions of furniture, equipment and other assets					-772,000
Net cash provided by (used in) investing activities					261,728,000		120,000,000
Financing Activities:
Dividends paid to common shareholders					-7,181,000		-8,137,000
Repurchase of common shares					-302,765,000		-109,633,000
Proceeds from share-based compensation, including income tax benefits					14,462,000		2,554,000
Net cash provided by (used in) financing activities					-295,484,000		-115,216,000
Effect of foreign currency exchange rate changes on cash and cash equivalents					0		0
Net increase (decrease) in cash and cash equivalents					-42,480,000		-3,090,000
Cash and cash equivalents at beginning of period					70,604,000		47,791,000
Cash and cash equivalents at end of period	28,124,000		44,701,000		28,124,000		44,701,000
Platinum Finance [Member]
ASSETS
Total investments	126,000				126,000					181,000
Investment in subsidiaries	680,845,000				680,845,000					636,814,000
Cash and cash equivalents	148,204,000		104,816,000		148,204,000		104,816,000
Reinsurance assets	0				0					0
Other assets	1,808,000				1,808,000					2,884,000
Total assets	830,983,000				830,983,000					792,001,000
Liabilities
Reinsurance liabilities	0				0					0
Debt obligations	250,000,000				250,000,000					250,000,000
Other liabilities	6,334,000				6,334,000					1,647,000
Total liabilities	256,334,000				256,334,000					251,647,000
Shareholders' Equity
Common shares	0				0					0
Additional paid-in capital	214,660,000				214,660,000					213,736,000
Accumulated other comprehensive income	20,252,000				20,252,000					41,386,000
Retained earnings	339,737,000				339,737,000					285,232,000
Total shareholders' equity	574,649,000				574,649,000					540,354,000
Total liabilities and shareholders' equity	830,983,000				830,983,000					792,001,000
Revenue:
Net premiums earned	0		0		0		0
Net investment income (expense)	-43,000		-3,000		-73,000		-10,000
Net realized gains (losses) on investments	0		0		0		0
Net impairment losses on investments	0		0		0		0
Other income (expense)	0		1,000		4,000		2,000
Total revenue	-43,000		-2,000		-69,000		-8,000
Expenses:
Net losses and loss adjustment expenses	0		0		0		0
Net acquisition expenses	0		0		0		0
Operating expenses	37,000		49,000		110,000		182,000
Net foreign currency exchange losses (gains)	0		0		0		0
Interest expense	4,782,000		4,775,000		14,341,000		14,321,000
Total expenses	4,819,000		4,824,000		14,451,000		14,503,000
Income (loss) before income taxes	-4,862,000		-4,826,000		-14,520,000		-14,511,000
Income tax expense (benefit)	-1,589,000		-1,625,000		-4,785,000		-4,890,000
Income (loss) before equity in earnings of subsidiaries	-3,273,000		-3,201,000		-9,735,000		-9,621,000
Equity in earnings of subsidiaries	29,948,000		8,175,000		64,241,000		40,116,000
Net income (loss)	26,675,000		4,974,000		54,506,000		30,495,000
Comprehensive Income (Loss) [Abstract]
Net income (loss)	26,675,000		4,974,000		54,506,000		30,495,000
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	0		0		0		0
Change in net unrealized gains and losses on all other securities	0		-2,000		-2,000		-3,000
Total change in net unrealized gains and losses	0		-2,000		-2,000		-3,000
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments	0		0		0		0
Net impairment losses on investments	0		0		0		0
Total reclassifications to net income	0		0		0		0
Other comprehensive income (loss) before income taxes	0		-2,000		-2,000		-3,000
Income tax benefit (expense)	-1,000		1,000		1,000		2,000
Other comprehensive income (loss)	-1,000		-1,000		-1,000		-1,000
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries	-1,049,000		1,356,000		-21,133,000		3,883,000
Comprehensive income (loss)	25,625,000		6,329,000		33,372,000		34,377,000
Net cash provided by (used in) operating activities					-3,970,000		-3,507,000
Proceeds from the sales of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Proceeds from maturities or paydowns of:
Fixed maturity available-for-sale securities					52,000		63,000
Short-term investments					0		0
Acquisitions of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Dividends from subsidiaries					0		0
Acquisitions of furniture, equipment and other assets					0
Net cash provided by (used in) investing activities					52,000		63,000
Financing Activities:
Dividends paid to common shareholders					0		0
Repurchase of common shares					0		0
Proceeds from share-based compensation, including income tax benefits					0		0
Net cash provided by (used in) financing activities					0		0
Effect of foreign currency exchange rate changes on cash and cash equivalents					0		0
Net increase (decrease) in cash and cash equivalents					-3,918,000		-3,444,000
Cash and cash equivalents at beginning of period					152,122,000		108,260,000
Cash and cash equivalents at end of period	148,204,000		104,816,000		148,204,000		104,816,000
Non-Guarantor Subsidiaries [Member]
ASSETS
Total investments	2,011,493,000	[1]			2,011,493,000	[1]				2,227,118,000	[1]
Investment in subsidiaries	574,649,000	[1]			574,649,000	[1]				540,354,000	[1]
Cash and cash equivalents	1,389,077,000	[1]	1,513,162,000		1,389,077,000	[1]	1,513,162,000
Reinsurance assets	293,775,000	[1]			293,775,000	[1]				277,279,000	[1]
Other assets	124,404,000	[1]			124,404,000	[1]				96,449,000	[1]
Total assets	4,393,398,000	[1]			4,393,398,000	[1]				4,638,869,000	[1]
Liabilities
Reinsurance liabilities	1,963,712,000	[1]			1,963,712,000	[1]				2,140,241,000	[1]
Debt obligations	0	[1]			0	[1]				0	[1]
Other liabilities	81,835,000	[1]			81,835,000	[1]				39,996,000	[1]
Total liabilities	2,045,547,000	[1]			2,045,547,000	[1]				2,180,237,000	[1]
Shareholders' Equity
Common shares	8,000,000	[1]			8,000,000	[1]				8,000,000	[1]
Additional paid-in capital	2,022,889,000	[1]			2,022,889,000	[1]				2,021,045,000	[1]
Accumulated other comprehensive income	77,638,000	[1]			77,638,000	[1]				179,071,000	[1]
Retained earnings	239,324,000	[1]			239,324,000	[1]				250,516,000	[1]
Total shareholders' equity	2,347,851,000	[1]			2,347,851,000	[1]				2,458,632,000	[1]
Total liabilities and shareholders' equity	4,393,398,000	[1]			4,393,398,000	[1]				4,638,869,000	[1]
Revenue:
Net premiums earned	135,360,000	[1]	138,588,000	[1]	405,146,000	[1]	421,875,000	[1]
Net investment income (expense)	17,800,000	[1]	23,210,000	[1]	54,160,000	[1]	77,921,000	[1]
Net realized gains (losses) on investments	-306,000	[1]	22,982,000	[1]	24,698,000	[1]	70,299,000	[1]
Net impairment losses on investments	-65,000	[1]	-699,000	[1]	-2,002,000	[1]	-2,882,000	[1]
Other income (expense)	277,000	[1]	-1,497,000	[1]	-3,495,000	[1]	-4,355,000	[1]
Total revenue	153,066,000	[1]	182,584,000	[1]	478,507,000	[1]	562,858,000	[1]
Expenses:
Net losses and loss adjustment expenses	44,142,000	[1]	45,117,000	[1]	120,807,000	[1]	191,430,000	[1]
Net acquisition expenses	30,675,000	[1]	26,168,000	[1]	91,207,000	[1]	87,025,000	[1]
Operating expenses	14,009,000	[1]	14,075,000	[1]	41,158,000	[1]	39,846,000	[1]
Net foreign currency exchange losses (gains)	487,000	[1]	541,000	[1]	-592,000	[1]	763,000	[1]
Interest expense	0	[1]	0	[1]	0	[1]	0	[1]
Total expenses	89,313,000	[1]	85,901,000	[1]	252,580,000	[1]	319,064,000	[1]
Income (loss) before income taxes	63,753,000	[1]	96,683,000	[1]	225,927,000	[1]	243,794,000	[1]
Income tax expense (benefit)	16,719,000	[1]	4,178,000	[1]	29,127,000	[1]	15,465,000	[1]
Income (loss) before equity in earnings of subsidiaries	47,034,000	[1]	92,505,000	[1]	196,800,000	[1]	228,329,000	[1]
Equity in earnings of subsidiaries	26,675,000	[1]	4,974,000	[1]	54,506,000	[1]	30,495,000	[1]
Net income (loss)	73,709,000	[1]	97,479,000	[1]	251,306,000	[1]	258,824,000	[1]
Comprehensive Income (Loss) [Abstract]
Net income (loss)	73,709,000	[1]	97,479,000	[1]	251,306,000	[1]	258,824,000	[1]
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	14,000	[1]	354,000	[1]	-600,000	[1]	263,000	[1]
Change in net unrealized gains and losses on all other securities	-7,622,000	[1]	24,213,000	[1]	-65,837,000	[1]	73,307,000	[1]
Total change in net unrealized gains and losses	-7,608,000	[1]	24,567,000	[1]	-66,437,000	[1]	73,570,000	[1]
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments	0	[1]	-22,710,000	[1]	-27,243,000	[1]	-70,607,000	[1]
Net impairment losses on investments	65,000	[1]	699,000	[1]	2,002,000	[1]	2,882,000	[1]
Total reclassifications to net income	65,000		-22,011,000		-25,241,000	[1]	-67,725,000	[1]
Other comprehensive income (loss) before income taxes	-7,543,000	[1]	2,556,000	[1]	-91,678,000	[1]	5,845,000	[1]
Income tax benefit (expense)	567,000	[1]	-730,000	[1]	11,379,000	[1]	-2,092,000	[1]
Other comprehensive income (loss)	-6,976,000		1,826,000		-80,299,000		3,753,000
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries	-1,050,000		1,355,000		-21,134,000		3,882,000
Comprehensive income (loss)	65,683,000		100,660,000		149,873,000		266,459,000
Net cash provided by (used in) operating activities					-481,000		-7,588,000
Proceeds from the sales of:
Fixed maturity available-for-sale securities					203,571,000		558,848,000
Short-term investments					11,857,000		36,581,000
Proceeds from maturities or paydowns of:
Fixed maturity available-for-sale securities					155,194,000		213,440,000
Short-term investments					209,240,000		663,011,000
Acquisitions of:
Fixed maturity available-for-sale securities					-291,006,000		-202,729,000
Short-term investments					-121,306,000		-266,723,000
Dividends from subsidiaries					0		0
Acquisitions of furniture, equipment and other assets					-5,416,000
Net cash provided by (used in) investing activities					162,134,000		1,002,428,000
Financing Activities:
Dividends paid to common shareholders					-262,500,000		-120,000,000
Repurchase of common shares					0		0
Proceeds from share-based compensation, including income tax benefits					0		0
Net cash provided by (used in) financing activities					-262,500,000		-120,000,000
Effect of foreign currency exchange rate changes on cash and cash equivalents					-7,745,000		1,863,000
Net increase (decrease) in cash and cash equivalents					-108,592,000		876,703,000
Cash and cash equivalents at beginning of period					1,497,669,000	[1]	636,459,000
Cash and cash equivalents at end of period	1,389,077,000	[1]	1,513,162,000		1,389,077,000	[1]	1,513,162,000
Consolidation, Eliminations [Member]
ASSETS
Total investments	0				0					0
Investment in subsidiaries	-2,922,500,000				-2,922,500,000					-2,998,986,000
Cash and cash equivalents	0		0		0		0
Reinsurance assets	0				0					0
Other assets	0				0					0
Total assets	-2,922,500,000				-2,922,500,000					-2,998,986,000
Liabilities
Reinsurance liabilities	0				0					0
Debt obligations	0				0					0
Other liabilities	0				0					0
Total liabilities	0				0					0
Shareholders' Equity
Common shares	-8,000,000				-8,000,000					-8,000,000
Additional paid-in capital	-2,237,549,000				-2,237,549,000					-2,234,781,000
Accumulated other comprehensive income	-97,890,000				-97,890,000					-220,457,000
Retained earnings	-579,061,000				-579,061,000					-535,748,000
Total shareholders' equity	-2,922,500,000				-2,922,500,000					-2,998,986,000
Total liabilities and shareholders' equity	-2,922,500,000				-2,922,500,000					-2,998,986,000
Revenue:
Net premiums earned	0		0		0		0
Net investment income (expense)	0		0		0		0
Net realized gains (losses) on investments	0		0		0		0
Net impairment losses on investments	0		0		0		0
Other income (expense)	0		0		0		0
Total revenue	0		0		0		0
Expenses:
Net losses and loss adjustment expenses	0		0		0		0
Net acquisition expenses	0		0		0		0
Operating expenses	0		0		0		0
Net foreign currency exchange losses (gains)	0		0		0		0
Interest expense	0		0		0		0
Total expenses	0		0		0		0
Income (loss) before income taxes	0		0		0		0
Income tax expense (benefit)	0		0		0		0
Income (loss) before equity in earnings of subsidiaries	0		0		0		0
Equity in earnings of subsidiaries	-100,384,000		-102,453,000		-305,812,000		-289,319,000
Net income (loss)	-100,384,000		-102,453,000		-305,812,000		-289,319,000
Comprehensive Income (Loss) [Abstract]
Net income (loss)	-100,384,000		-102,453,000		-305,812,000		-289,319,000
Other comprehensive income (loss) on available-for-sale securities before reclassifications:
Change in net unrealized gains and losses on securities with other-than-temporary impairments recorded	0		0		0		0
Change in net unrealized gains and losses on all other securities	0		0		0		0
Total change in net unrealized gains and losses	0		0		0		0
Reclassifications to net income on available-for-sale securities:
Net realized gains on investments	0		0		0		0
Net impairment losses on investments	0		0		0		0
Total reclassifications to net income	0		0		0		0
Other comprehensive income (loss) before income taxes	0		0		0		0
Income tax benefit (expense)	0		0		0		0
Other comprehensive income (loss)	0		0		0		0
Other comprehensive income (loss) due to change in accumulated other comprehensive income (loss) of subsidiaries	9,076,000		-4,536,000		122,567,000		-11,517,000
Comprehensive income (loss)	-91,308,000		-106,989,000		-183,245,000		-300,836,000
Net cash provided by (used in) operating activities					-923,000		0
Proceeds from the sales of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Proceeds from maturities or paydowns of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Acquisitions of:
Fixed maturity available-for-sale securities					0		0
Short-term investments					0		0
Dividends from subsidiaries					-262,500,000		-120,000,000
Acquisitions of furniture, equipment and other assets					0
Net cash provided by (used in) investing activities					-262,500,000		-120,000,000
Financing Activities:
Dividends paid to common shareholders					262,500,000		120,000,000
Repurchase of common shares					0		0
Proceeds from share-based compensation, including income tax benefits					923,000		0
Net cash provided by (used in) financing activities					263,423,000		120,000,000
Effect of foreign currency exchange rate changes on cash and cash equivalents					0		0
Net increase (decrease) in cash and cash equivalents					0		0
Cash and cash equivalents at beginning of period					0		0
Cash and cash equivalents at end of period	$0		$0		$0		$0
[1]	Amounts represent an aggregation of the non-guarantor subsidiaries and exclude consolidating adjustments.