Organization & Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Cash	Cash Cash includes cash on hand and demand deposits with banks, excluding such amounts held by Syndicate 1221 included as Funds at Lloyd’s.
Investments	Investments As of December 31, 2014 and 2013, all fixed maturity and equity securities held by our Company were carried at fair value and classified as available-for-sale. Available-for-sale securities are debt and equity securities not classified as either held-to-maturity securities or trading securities and are reported at fair value, with unrealized gains and losses excluded from earnings and reported in accumulated other comprehensive income (“AOCI”) as a separate component of stockholders’ equity. Fixed maturity securities include bonds, mortgage-backed and asset-backed securities. Equity securities consist of common stock and preferred stock. Short-term investments are carried at fair value. Short-term investments mature within one year from the purchase date. All prices for our fixed maturities, equity securities and short-term investments valued as Level 1, Level 2 or Level 3 in the fair value hierarchy, as defined in the Financial Accounts Standards Board (“FASB”) Accounting Standards Codification 820 (“ASC 820”), Fair Value Measurements, are received from independent pricing services utilized by one of our outside investment managers whom we employ to assist us with investment accounting services. This manager utilizes a pricing committee, which approves the use of one or more independent pricing service vendors. The pricing committee consists of five or more members of the investment management firm, one from senior management and one from the accounting group with the remainder from the asset class specialists and client strategists. The pricing source of each security is determined in accordance with the pricing source procedures approved by the pricing committee. The investment manager uses supporting documentation received from the independent pricing service vendor detailing the inputs, models and processes used in the independent pricing service vendors’ evaluation process to determine the appropriate fair value hierarchy. Any pricing where the input is believed to be unobservable is deemed to be a Level 3 price. Management has reviewed this process by which the manager determines the prices and has obtained alternative pricing to validate a sample of the prices and assess their reasonableness. Premiums and discounts on fixed maturity securities are amortized into interest income over the life of the security under the interest method. For mortgage-backed and asset-backed securities, anticipated prepayments and expected maturities are utilized in applying the interest rate method. An effective yield is calculated based on projected principal cash flows at the time of original purchase. The effective yield is used to amortize the purchase price of the security over the security’s expected life. Book values are adjusted to reflect the amortization of premium or accretion of discount on a monthly basis. The projected principal cash flows are based on certain prepayment assumptions, which are generated using a prepayment model. The prepayment model uses a number of factors to estimate prepayment activity including the current levels of interest rates (refinancing incentive), time of year (seasonality), economic activity (including housing turnover) and term and age of the underlying collateral (burnout, seasoning). Prepayment assumptions associated with the mortgage-backed and asset-backed securities are reviewed on a periodic basis. When changes in prepayment assumptions are deemed necessary as the result of actual prepayments differing from anticipated prepayments, securities are revalued based upon the new prepayment assumptions utilizing the retrospective adjustment method, whereby the effective yield is recalculated to reflect actual payments to date and anticipated future payments. The investment in such securities is adjusted to the amount that would have existed had the new effective yield been applied since the acquisition of the security. Such adjustments, if any, are included in net investment income for the current period being reported. Realized gains and losses on sales of investments are recognized when the related trades are executed and are determined on the basis of the specific identification method.
Impairment of Invested Assets	Impairment of Invested Assets Management regularly reviews our fixed maturity and equity securities portfolios to evaluate the necessity of recording impairment losses for other-than-temporary declines in the fair value of securities. For fixed maturity securities, we consider our intent to sell a security and whether it is more likely than not that, we will be required to sell a security before the anticipated recovery as part of the process of evaluating whether a security’s unrealized loss represents an other-than-temporary decline. For fixed maturity securities that have a fair value below amortized cost and that we intend to sell or for which it is more likely than not that we would be required to sell, an other than temporary impairment (“OTTI”) loss is recognized in earnings by writing such security down to fair value. For fixed maturity securities we do not intend to sell or for which it is more likely than not our Company would not be required to sell, a decline in value below amortized cost is only recognized to the extent the present value of future cash flows expected to be collected is less than the amortized cost of the security. Such shortfall in the present value of future cash flows is considered the credit loss and is recognized as an OTTI loss in earnings, with the non-credit portion of the impairment (i.e. the difference between the present value of future cash flows and fair value of the security) recognized as OTTI losses in other comprehensive income (“OCI”). In evaluating OTTI of equity securities, we consider our intent to hold the securities as part of the process of evaluating whether a decline in fair value below cost represents an other than temporary decline in value. For equity securities in an unrealized loss position that we do not intent to hold or that we do not expect to recover their value within a reasonable period of time, a net OTTI loss is recognized in earnings by writing such security down to the fair value.
Syndicate 1221	Syndicate 1221 Syndicate 1221 reports the amount of premiums, claims, and expenses recorded in an underwriting account for a particular year over a three year period. Traditionally, three years have been necessary to report substantially all premiums associated with an underwriting year and to report most of the related claims, although claims may remain unsettled after the underwriting year is closed. Syndicate 1221 typically closes an underwriting year by reinsuring outstanding claims in that underwriting year with the next underwriting year. Only profits from closed underwriting years of account are distributed to NCUL. Profits from open underwriting years of account are not available and therefore not distributed to NCUL until the end of the three year period. Our Company’s financial statements include all of the assets, liabilities, revenues and expenses of Syndicate1221. Adjustments are recorded to recognize underwriting results as incurred in the specific year and not over a three year period. Syndicate 1221 is not a separate legal entity. Refer to Note 10, Lloyd’s Syndicate 1221, for additional information.
Foreign Currency Remeasurement and Translation	Foreign Currency Remeasurement and Translation The functional currency in each of our operations is generally the currency of the local operating environment, except for our Lloyd’s Operations which is the U.S. dollar. Transactions in currencies other than an operation’s functional currency are remeasured into the functional currency and the resulting foreign exchange gains and losses are reflected in net Other Income (Expense) in the Consolidated Statements of Income. Functional currency assets and liabilities are translated into U.S. dollars using period end rates of exchange and the related translation adjustments are recorded as a separate component of AOCI. Statement of income amounts expressed in functional currencies are translated using average exchange rates. During the first quarter, Syndicate 1221 revised its foreign exchange accounting methodology from reporting its financial position and results using three functional currencies (GBP, USD and CAD) to one functional currency (USD). The USD was chosen as the single functional currency as the majority of the Syndicate’s insurance business has been and continues to be transacted in USD. This cumulative change in re-measurement has resulted in an immaterial correction of $10.0 million ($6.6 million, after-tax) reducing Accumulated Other Comprehensive Income in the consolidated balance sheet, offset by a gain in Other Income in the consolidated statement of income. The impact of the correction is not material to the previously issued annual financial statements for 2013 and 2012.
Premium Revenues	Premium Revenues Written premium is recorded based on the insurance policies that have been reported to us and the policies that have been written by agents but not yet reported to us. We estimate the amount of written premium not yet reported based on judgments relative to current and historical trends of the business being written. Such estimates are regularly reviewed and updated and any resulting adjustments are included in the current year’s results. An unearned premium reserve is established to reflect the unexpired portion of each policy at the financial reporting date. Substantially all of our business is placed through agents and brokers. We record estimates for both unreported direct and assumed premiums. We also record the ceded portion of the estimated gross written premium and related acquisition costs. The earned gross, ceded and net premiums are calculated based on our earning methodology, which is generally pro-rata over the policy period or over the period of risk if the period of risk differs significantly from the contract period. A portion of our premium is estimated for unreported premium, mostly for the Marine business written by our U.K. Branch and Lloyd’s Operations as well as the Accident & Health (“A&H”) and Latin American & Caribbean Property Casualty and Surety Reinsurance business written by NavRe. Such premium estimates are generally based on submission data received from brokers and agents and recorded when the insurance policy or reinsurance contract is written or bound. The estimates are regularly reviewed and updated taking into account the premium received to date versus the estimate and the age of the estimate. To the extent that the actual premium varies from the estimates, the difference, along with the related loss reserves and underwriting expenses, is recorded in current operations.
Reinsurance Ceded	Reinsurance Ceded In the normal course of business, reinsurance is purchased by us from insurers or reinsurers to reduce the amount of loss arising from claims. In order to determine the proper accounting for the reinsurance, management analyzes the reinsurance agreements to determine whether the reinsurance should be classified as prospective or retroactive based upon the terms of the reinsurance agreement and whether the reinsurer has assumed significant insurance risk to the extent that the reinsurer may realize a significant loss from the transaction. Prospective reinsurance is reinsurance in which an assuming company agrees to reimburse the ceding company for losses that may be incurred as a result of future insurable events covered under contracts subject to the reinsurance. Retroactive reinsurance is reinsurance in which an assuming company agrees to reimburse a ceding company for liabilities incurred as a result of past insurable events covered under contracts subject to the reinsurance. Ceded reinsurance premiums and any related ceding commission and ceded losses are reflected as reductions of the respective income or expense accounts over the terms of the reinsurance contracts. Prepaid reinsurance premiums represent the portion of premiums ceded to reinsurers applicable to the unexpired terms of the reinsurance contracts in force. Reinsurance reinstatement premiums are recognized in the same period as the loss event that gave rise to the reinstatement premiums. Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policy. Unearned premiums ceded and estimates of amounts recoverable from reinsurers on paid and unpaid losses are reflected as assets. Provisions are made for estimated unrecoverable reinsurance.
Deferred Policy Acquisition Costs	Deferred Policy Acquisition Costs Costs of acquiring business are deferred and amortized ratably over the period that the related premiums are recognized as revenue. Such costs (e.g., commission expense, other underwriting expenses and premium taxes) are limited to the incremental direct costs related to the successful acquisition of new or renewal business. The method of computing deferred policy acquisition costs limits the deferral to their estimated net realizable value based on the related unearned premiums and takes into account anticipated losses and loss adjustment expenses, commission expense and operating expenses based on historical and current experience as well as anticipated investment income.
Reserves for Losses and Loss Adjustment Expenses	Reserves for Losses and Loss Adjustment Expenses Unpaid losses and loss adjustment expenses are determined on an individual basis for claims reported on direct business for insureds, from reports received from ceding insurers for insurance assumed from such insurers and on estimates based on Company and industry experience for incurred but not reported (“IBNR”) claims and loss adjustment expenses. Indicated IBNR loss reserves are calculated by our actuaries using several standard actuarial methodologies, including the paid and incurred loss development and the paid and incurred Bornheutter-Ferguson loss methods. Additional analyses, such as frequency/severity analyses, are performed for certain books of business. The provision for unpaid losses and loss adjustment expenses has been established to cover the estimated unpaid cost of claims incurred. Such estimates are regularly reviewed and updated and any resulting adjustments are included in the current year’s results. Management believes that the liability it has recognized for unpaid losses and loss adjustment expenses is a reasonable estimate of the ultimate unpaid claims incurred, however, such provisions are necessarily based on estimates and, accordingly, no representation is made that the ultimate liability will not differ materially from the amounts recorded in the accompanying consolidated financial statements. Losses and loss adjustment expenses are recorded on an undiscounted basis.
Earnings per Share	Earnings per Share Basic earnings per share (“EPS”) is computed by dividing net income by the weighted average number of common shares outstanding for the period. Diluted earnings per share reflects the basic earnings per share adjusted for the potential dilution that would occur if all issued stock options were exercised and all stock grants were fully vested.
Depreciation and Amortization	Depreciation and Amortization Depreciation of furniture and fixtures, electronic data processing equipment and computer software is provided over the estimated useful lives of the respective assets, ranging from three to seven years, using the straight-line method. Amortization of leasehold improvements is provided over the shorter of the useful lives of those improvements or the contractual terms of the leases using the straight-line method.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the excess-of-cost of acquiring a business enterprise over the fair value of the net assets acquired. Our Company has also recorded indefinite lived intangible assets related to the acquisition of the remaining non-controlled stamp capacity of Lloyd’s Syndicate 1221. Goodwill and indefinite lived intangible assets are reported at carrying value and are tested for impairment at least annually, and when permitted by the applicable accounting guidance, qualitative factors are assessed to determine whether it is necessary to calculate an asset’s fair value when testing an asset with an indefinite life for impairment. Goodwill and indefinite lived intangible assets are considered impaired if the estimated fair value is less than its carrying value and any impairment loss is measured as the difference between the implied fair value and the carrying value. This Company did not recognize an impairment on goodwill or the indefinite lived intangible assets for any of the years ended December 31, 2014, 2013 and 2012. As of December 31, 2014, the carrying value of goodwill and indefinite lived intangible assets was $7.0 million, consisting of $2.5 million and $2.4 million of goodwill assigned to NMC and our Lloyd’s Operations, respectively, and $2.1 million of indefinite lived intangible assets assigned to our Lloyd’s Operations. As of December 31, 2013, the carrying value of goodwill and indefinite lived intangible assets was $7.2 million, consisting of $2.5 million and $2.4 million of goodwill assigned to NMC and our Lloyd’s Operations, respectively, and $2.3 million of indefinite lived intangible assets assigned to our Lloyd’s Operations. Changes in the carrying value of the goodwill and indefinite lived intangible assets are due to fluctuations in currency exchange rates between the U.S. dollar and the British pound.
Income Taxes	Income Taxes We apply the asset and liability method of accounting for income taxes whereby deferred assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. In assessing the realization of deferred tax assets, management considers whether it is more likely than not that, the deferred tax assets will be realized. These reviews include, among other factors, the nature and amount of the taxable income and expense items, the expected timing of when assets will be used or liabilities will be required to be reported, as well as the reliability of historical profitability of businesses expected to provide future earnings. After review, if management determines that the realization of the tax asset does not meet the more likely than not criterion an offsetting valuation allowance is recorded, which reduces net earnings and the deferred tax asset in that period. Additional information regarding our deferred tax assets can be found in Note 7, Income Taxes, in the Notes to Consolidated Financial Statements, included herein.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires the use of 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 period. The accounting estimates that are viewed by management as critical are those in connection with reserves for losses and loss adjustment expenses, reinsurance recoverables, written and unearned premiums, the recoverability of deferred tax assets, and impairment of invested assets.