National General (NTTNP) 10-Q 7 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Statement - shares	3 Months Ended
	Mar. 31, 2018	May 03, 2018
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	NGHC
Entity Registrant Name	National General Holdings Corp.
Entity Central Index Key	1,578,735
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		106,923,327

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Investments:
Debt securities, available-for-sale, at fair value (Exchanges - $310,740 and $304,934)	$ 3,244,320	$ 3,139,889
Equity securities, at fair value	50,157	50,341
Short-term investments (Exchanges - $21,825 and $22,279)	39,969	38,266
Other investments (related parties - $241,801 and $347,548)	315,870	421,292
Total investments	3,650,316	3,649,788
Cash and cash equivalents (Exchanges - $5,880 and $5,442)	321,937	292,282
Restricted cash and cash equivalents (Exchanges - $674 and $609)	56,116	65,202
Accrued investment income (related parties - $1,174 and $2,334) (Exchanges - $2,229 and $1,805)	23,091	22,372
Premiums and other receivables, net (Exchanges - $49,581 and $56,792)	1,497,871	1,324,321
Deferred acquisition costs (Exchanges - $21,635 and $20,837)	233,600	216,389
Reinsurance recoverable (related parties - $11,399 and $15,688) (Exchanges - $107,250 and $94,204)	1,334,726	1,294,165
Prepaid reinsurance premiums (Exchanges - $97,248 and $100,980)	528,770	517,122
Premises and equipment, net (Exchanges - $3,527 and $4,269)	316,392	324,049
Intangible assets, net (Exchanges - $3,640 and $3,685)	397,406	404,070
Goodwill	174,153	174,153
Prepaid and other assets (Exchanges - $2,318 and $2,263)	134,768	155,830
Total assets	8,669,146	8,439,743
Liabilities:
Unpaid loss and loss adjustment expense reserves (Exchanges - $158,796 and $143,353)	2,678,917	2,663,557
Unearned premiums and other revenue (Exchanges - $228,198 and $225,395)	2,230,544	2,032,605
Reinsurance payable (Exchanges - $58,554 and $68,275)	437,071	398,047
Accounts payable and accrued expenses (related parties - $72,641 and $140,057) (Exchanges - $10,140 and $8,827)	411,547	431,881
Debt	713,893	713,710
Other liabilities (Exchanges - $55,513 and $41,582)	232,521	246,518
Total liabilities	6,704,493	6,486,318
Stockholders’ equity:
Common stock, $0.01 par value - authorized 150,000,000 shares, issued and outstanding 106,887,566 shares - 2018; authorized 150,000,000 shares, issued and outstanding 106,697,648 shares - 2017.	1,069	1,067
Preferred stock, $0.01 par value - authorized 10,000,000 shares, issued and outstanding 2,565,000 shares - 2018; authorized 10,000,000 shares, issued and outstanding 2,565,000 shares - 2017. Aggregate liquidation preference $420,000 - 2018, $420,000 - 2017.	420,000	420,000
Additional paid-in capital	919,029	917,751
Accumulated other comprehensive income:
Unrealized foreign currency translation adjustment, net of tax	(8,529)	(7,810)
Unrealized losses on investments, net of tax	(37,193)	(302)
Total accumulated other comprehensive income (loss)	(45,722)	(8,112)
Retained earnings	662,713	597,863
Total National General Holdings Corp. Stockholders’ Equity	1,957,089	1,928,569
Non-controlling interest	7,564	24,856
Total stockholders’ equity	1,964,653	1,953,425
Total liabilities and stockholders’ equity	$ 8,669,146	$ 8,439,743

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	106,887,566	106,697,648
Common stock, shares outstanding	106,887,566	106,697,648
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	2,565,000	2,565,000
Preferred stock, shares outstanding	2,565,000	2,565,000
Aggregate liquidation preference	$ 420,000	$ 420,000
Debt Securities	3,244,320	3,139,889
Short-term investments	39,969	38,266
Other investments	315,870	421,292
Cash and cash equivalents	321,937	292,282
Restricted cash and cash equivalents	56,116	65,202
Accrued investment income	23,091	22,372
Premiums and other receivables, net	1,497,871	1,324,321
Deferred acquisition costs	233,600	216,389
Reinsurance recoverable	1,334,726	1,294,165
Prepaid reinsurance premiums	528,770	517,122
Premises and equipment, net	316,392	324,049
Intangible assets, net	397,406	404,070
Prepaid and other assets	134,768	155,830
Unpaid loss and loss adjustment expense reserves	2,678,917	2,663,557
Unearned premiums and other revenue	2,230,544	2,032,605
Reinsurance payable	437,071	398,047
Accounts payable and accrued expenses	411,547	431,881
Other liabilities	232,521	246,518
Related Parties
Other investments	241,801	347,548
Accrued investment income	1,174	2,334
Reinsurance recoverable	11,399	15,688
Accounts payable and accrued expenses	72,641	140,057
Reciprocal Exchanges
Debt Securities	310,740	304,934
Short-term investments	21,825	22,279
Cash and cash equivalents	5,880	5,442
Restricted cash and cash equivalents	674	609
Accrued investment income	2,229	1,805
Premiums and other receivables, net	49,581	56,792
Deferred acquisition costs	21,635	20,837
Reinsurance recoverable	107,250	94,204
Prepaid reinsurance premiums	97,428	100,980
Premises and equipment, net	3,527	4,269
Intangible assets, net	3,640	3,685
Prepaid and other assets	2,318	2,263
Unpaid loss and loss adjustment expense reserves	158,796	143,353
Unearned premiums and other revenue	228,198	225,395
Reinsurance payable	58,554	68,275
Accounts payable and accrued expenses	10,140	8,827
Other liabilities	$ 55,513	$ 41,582

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Net earned premium	$ 905,538	$ 918,485
Ceding commission income	44,468	19,994
Service and fee income	142,122	125,942
Net investment income	25,011	29,044
Net gain (loss) on investments	118	(1,412)
Other income	0	9,801
Total revenues	1,117,257	1,101,854
Expenses:
Loss and loss adjustment expense	634,166	618,817
Acquisition costs and other underwriting expenses	168,710	174,720
General and administrative expenses	231,005	255,185
Interest expense	11,154	11,545
Total expenses	1,045,035	1,060,267
Income before provision for income taxes	72,222	41,587
Provision for income taxes	16,202	10,789
Net income	56,020	30,798
Net (income) loss attributable to non-controlling interest	12,188	6,125
Net income attributable to NGHC	68,208	36,923
Dividends on preferred stock	(7,875)	(7,875)
Net income attributable to NGHC common stockholders	$ 60,333	$ 29,048
Earnings per common share:
Basic (usd per share)	$ 0.57	$ 0.27
Diluted (usd per share)	0.55	0.27
Dividends declared per common share (usd per common share)	$ 0.04	$ 0.04
Weighted average common shares outstanding:
Basic (in shares)	106,758,641	106,467,599
Diluted (in shares)	108,950,984	109,166,681

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 56,020	$ 30,798
Other comprehensive income, net of tax:
Foreign currency translation adjustment, net of tax (tax - $(188) and $(385))	(719)	(714)
Gross gain (loss) on investments, net of tax (tax - $(11,173) and $6,616)	(42,033)	12,286
Reclassification adjustments for investment gain/loss included in net income:
Other (gain) loss on investments, net of tax (tax - $0 and $(1,260))	2	(2,341)
Other comprehensive income (loss), net of tax	(42,750)	9,231
Comprehensive income	13,270	40,029
Comprehensive (income) loss attributable to non-controlling interest	17,292	5,299
Comprehensive income attributable to NGHC	$ 30,562	$ 45,328

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment, net of tax (tax - $(188) and $(385))	$ (188)	$ (385)
Gross gain (loss) on investments, net of tax (tax - $(11,173) and $6,616)	(11,173)	6,616
Other (gain) loss on investments, net of tax (tax - $0 and $(1,260))	$ 0	$ (1,260)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Preferred Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Non-controlling Interest
Common stock, shares outstanding, beginning balance at Dec. 31, 2016		106,428,092
Common stock, amount, beginning balance at Dec. 31, 2016		$ 1,064
Preferred stock, shares outstanding, beginning balance at Dec. 31, 2016			2,565,000
Preferred stock, amount, beginning balance at Dec. 31, 2016			$ 420,000
Total stockholders' equity, amount, beginning balance at Dec. 31, 2016	$ 1,917,358			$ 913,787	$ 11,475	$ 539,114	$ 31,918
Increase (Decrease) in Stockholders' Equity
Net income (loss)	30,798					36,923	(6,125)
Foreign currency translation adjustment, net of tax	(714)				(714)
Change in unrealized gain (loss) on investments, net of tax	9,945				9,119		826
Common stock dividends	(4,260)					(4,260)
Preferred stock dividends	(7,875)					(7,875)
Common stock issued under employee stock plans and exercises of stock options, shares		107,141
Common stock issued under employee stock plans and exercises of stock options, value	172	$ 1		171
Shares withheld related to net share settlement, shares		(32,983)
Shares withheld related to net share settlement	(834)			(834)
Stock-based compensation	2,180			2,180
Common stock, shares outstanding, ending balance at Mar. 31, 2017		106,502,250
Common stock, amount, ending balance at Mar. 31, 2017		$ 1,065
Preferred stock, shares outstanding, ending balance at Mar. 31, 2017			2,565,000
Preferred stock, amount, ending balance at Mar. 31, 2017			$ 420,000
Total stockholders' equity, amount, ending balance at Mar. 31, 2017	$ 1,946,770			915,304	19,880	563,902	26,619
Common stock, shares outstanding, beginning balance at Dec. 31, 2017	106,697,648	106,697,648
Common stock, amount, beginning balance at Dec. 31, 2017		$ 1,067
Preferred stock, shares outstanding, beginning balance at Dec. 31, 2017	2,565,000		2,565,000
Preferred stock, amount, beginning balance at Dec. 31, 2017			$ 420,000
Total stockholders' equity, amount, beginning balance at Dec. 31, 2017	$ 1,953,425			917,751	(8,112)	597,863	24,856
Increase (Decrease) in Stockholders' Equity
Cumulative-effect adjustment of change in accounting principles	8,830				36	8,794
Net income (loss)	56,020					68,208	(12,188)
Foreign currency translation adjustment, net of tax	(719)				(719)
Change in unrealized gain (loss) on investments, net of tax	(42,031)				(36,927)		(5,104)
Common stock dividends	(4,277)					(4,277)
Preferred stock dividends	(7,875)					(7,875)
Common stock issued under employee stock plans and exercises of stock options, shares		251,491
Common stock issued under employee stock plans and exercises of stock options, value	492	$ 2		490
Shares withheld related to net share settlement, shares		(61,573)
Shares withheld related to net share settlement	(1,342)			(1,342)
Stock-based compensation	$ 2,130			2,130
Common stock, shares outstanding, ending balance at Mar. 31, 2018	106,887,566	106,887,566
Common stock, amount, ending balance at Mar. 31, 2018		$ 1,069
Preferred stock, shares outstanding, ending balance at Mar. 31, 2018	2,565,000		2,565,000
Preferred stock, amount, ending balance at Mar. 31, 2018			$ 420,000
Total stockholders' equity, amount, ending balance at Mar. 31, 2018	$ 1,964,653			$ 919,029	$ (45,722)	$ 662,713	$ 7,564

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 56,020	$ 30,798
Reconciliation of net income to net cash provided by (used in) operating activities:
Net (gain) loss on investments	(118)	1,412
Bad debt expense	20,184	15,545
Depreciation and amortization	20,141	35,273
Stock-compensation expense	2,130	2,180
Deferred income taxes	(4,512)	(18,928)
Other, net	(2,576)	(7,687)
Changes in assets and liabilities:
Accrued investment income	(1,082)	(1,306)
Premiums and other receivables	(200,150)	(319,067)
Deferred acquisition costs	(20,755)	(21,790)
Reinsurance recoverable	(40,537)	(20,087)
Prepaid reinsurance premiums	(11,648)	(13,002)
Prepaid expenses and other assets	38,712	(5,801)
Unpaid loss and loss adjustment expense reserves	17,044	4,582
Unearned premiums and other revenue	213,465	231,123
Reinsurance payable	39,036	35,661
Accounts payable	(52,811)	118,396
Other liabilities	(20,601)	70,839
Net cash provided by operating activities	51,942	138,141
Cash flows from investing activities:
Purchases of debt securities, available-for-sale	(310,241)	(82,163)
Proceeds from sale and maturity of debt securities, available-for-sale	193,733	41,469
Purchases of equity securities	0	(23,433)
Proceeds from sale of equity securities	0	23,778
Purchases of debt securities, trading	0	(78,340)
Proceeds from sale and maturity of debt securities, trading	0	52,810
Purchases of short-term investments	(906,325)	(231,502)
Proceeds from sale of short-term investments	904,788	194,061
Purchases of other investments	(2,979)	(21,203)
Proceeds from sale and return of other investments	109,793	2,741
Purchases of premises and equipment	(5,716)	(17,704)
Acquisition of consolidated subsidiaries, net of cash	0	(16,968)
Net cash used in investing activities	(16,947)	(156,454)
Cash flows from financing activities:
Dividends paid to common shareholders	(4,268)	(4,257)
Dividends paid to preferred shareholders	(7,875)	(7,875)
Taxes paid related to net share settlement of equity awards	(1,342)	(834)
Other financing activities, net	492	128
Net cash used in financing activities	(12,993)	(12,838)
Effect of exchange rate changes on cash and cash equivalents	(1,433)	246
Net increase (decrease) in cash, cash equivalents, and restricted cash	20,569	(30,905)
Cash, cash equivalents, and restricted cash at beginning of the period	357,484	285,900
Cash, cash equivalents, and restricted cash at end of the period	378,053	254,995
Supplemental disclosures of non-cash investing and financing activities:
Unsettled securities purchases	27,598	106,858
Unsettled securities sales	10,962	82,173
Common Stock
Dividends Payable
Accrued stock dividends	4,277	4,260
Preferred Stock
Dividends Payable
Accrued stock dividends	$ 7,875	$ 7,875

Basis of Reporting

Basis of Reporting	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Reporting	Basis of Reporting The accompanying unaudited interim condensed consolidated financial statements include the accounts of National General Holdings Corp. and its subsidiaries (the “Company” or “NGHC”) and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial statements and with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the U.S. Securities and Exchange Commission (the “SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These interim condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 previously filed with the SEC on February 26, 2018 . The balance sheet at December 31, 2017 , has been derived from the audited consolidated financial statements at that date. The interim condensed consolidated financial statements as of and for the three months ended March 31, 2017 have been adjusted from the information set forth in the Form 10-Q for the quarterly period ended March 31, 2017 . See Note 3, “Revisions of Previously Issued Financial Statements” in the Company’s 2017 Form 10-K. These interim condensed consolidated financial statements reflect all adjustments that are, in the opinion of management, necessary for a fair presentation of the results for the interim period and all such adjustments are of a normal recurring nature. The results of operations for the interim period are not necessarily indicative, if annualized, of those to be expected for the full year. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates. The unaudited condensed consolidated financial statements include the accounts and operations of Adirondack Insurance Exchange, a New York reciprocal insurer, and New Jersey Skylands Insurance Association, a New Jersey reciprocal insurer (together with their subsidiaries, the “Exchanges” or “Reciprocal Exchanges”). The Company has no ownership interest in the Reciprocal Exchanges but manages their business operations and has the ability to direct their activities through its wholly-owned management companies. The Reciprocal Exchanges are property and casualty insurers. To conform to the current-year quarter presentation, the Company reclassified earnings (losses) of equity method investments with related parties as a component of net investment income on its condensed consolidated statements of income. A detailed description of the Company’s significant accounting policies and management judgments is located in the notes to the audited consolidated financial statements, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , filed with the SEC.
Basis of Accounting, Policy	The accompanying unaudited interim condensed consolidated financial statements include the accounts of National General Holdings Corp. and its subsidiaries (the “Company” or “NGHC”) and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial statements and with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the U.S. Securities and Exchange Commission (the “SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These interim condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 previously filed with the SEC on February 26, 2018 . The balance sheet at December 31, 2017 , has been derived from the audited consolidated financial statements at that date. The interim condensed consolidated financial statements as of and for the three months ended March 31, 2017 have been adjusted from the information set forth in the Form 10-Q for the quarterly period ended March 31, 2017 . See Note 3, “Revisions of Previously Issued Financial Statements” in the Company’s 2017 Form 10-K. These interim condensed consolidated financial statements reflect all adjustments that are, in the opinion of management, necessary for a fair presentation of the results for the interim period and all such adjustments are of a normal recurring nature. The results of operations for the interim period are not necessarily indicative, if annualized, of those to be expected for the full year. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted During 2018 In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” to remove inconsistencies and weaknesses in revenue requirements, provide a more robust framework for addressing revenue issues, improve comparability of revenue recognition practices, and provide improved disclosure requirements. While the guidance excludes revenue from insurance contracts, investments and financial instruments from its scope, the guidance is applicable to the Company’s service and fee income not specifically exempted from the guidance. The Company adopted ASU 2014-09 effective January 1, 2018, using the modified retrospective method and recorded a cumulative-effect adjustment to the opening balance sheet, increasing retained earnings by $8,830 . See Note 3 , “ Service and Fee Income ” for additional information. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” to provide users of financial statements with more useful information on the recognition, measurement, presentation, and disclosure of financial instruments. Specifically, under ASU 2016-01, equity investments (other than those accounted for using the equity method of accounting or those subject to consolidation) are to be measured at fair value with changes in fair value recognized in earnings. The Company adopted ASU 2016-01 effective January 1, 2018, and recorded a cumulative-effect adjustment to the opening balance sheet, increasing Accumulated Other Comprehensive Income (“AOCI”) by $36 and decreasing retained earnings by the same amount. To conform to the current-year quarter presentation, equity securities are presented in a single line in the Company’s condensed consolidated balance sheets and statements of cash flows. In October 2016, the FASB issued ASU 2016-16 “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory,” which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The Company adopted ASU 2016-16 effective January 1, 2018. Based on the intra-entity transfers of assets executed by the Company, the adoption of this guidance did not have an effect on the Company’s results of operations, financial position or liquidity. Not Yet Adopted With the exception of those adopted above or discussed below, there have been no recent accounting pronouncements, changes in accounting pronouncements, or quantitative or qualitative progress made towards implementation of outstanding accounting pronouncements during the three months ended March 31, 2018 , as compared to those described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , that are of significance, or potential significance, to the Company. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The new standard establishes a right-of-use (ROU) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for fiscal years beginning after December 15, 2018. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is in the early stages of evaluating the impact this guidance will have on its results of operations, financial position or liquidity and disclosures. The Company expects the adoption will have a significant impact on its consolidated financial statements, primarily to the consolidated balance sheets by recognizing a right-of-use asset and corresponding lease liability and related disclosures, due to the addition of operating leases previously accounted for as off-balance sheet transactions. The Company is currently unable to quantify the impact of adopting this guidance.

Service and Fee Income

Service and Fee Income	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Service and Fee Income	Service and Fee Income On January 1, 2018, the Company adopted ASU 2014-09 and all the related amendments (“ASC 606”) for in scope contracts with customers using the modified retrospective method. Financial statements presented prior to the adoption of ASC 606 are reported under the previous guidance of ASC 605, “Revenue Recognition.” ASC 606 is applicable to the Company’s service and fee income, primarily related to the recognition of commission revenue in the Accident and Health segment. Disaggregation of Revenue by Type and Operating Segment The following table summarizes revenue by type and operating segment within service and fee income: Three Months Ended March 31, 2018 2017 Property Accident (1) Total Property Accident Total Commission revenue $ 21,709 $ 17,524 $ 39,233 $ 29,745 $ 10,669 $ 40,414 Finance and processing fees 32,060 1,255 33,315 23,600 2,484 26,084 Installment fees 21,302 — 21,302 18,502 — 18,502 Group health administrative fees — 19,291 19,291 — 14,561 14,561 Late payment fees 7,558 25 7,583 7,600 31 7,631 Other service and fee income 14,306 7,092 21,398 14,222 4,528 18,750 Total $ 96,935 $ 45,187 $ 142,122 $ 93,669 $ 32,273 $ 125,942 NGHC $ 94,489 $ 45,187 $ 139,676 $ 91,589 $ 32,273 $ 123,862 Reciprocal Exchanges 2,446 — 2,446 2,080 — 2,080 Total $ 96,935 $ 45,187 $ 142,122 $ 93,669 $ 32,273 $ 125,942 (1) The impact to commission revenue for the three months ended March 31, 2018 was an increase of $2,501 as a result of applying ASC 606. Prior period amounts have not been adjusted under the modified retrospective method.

Investments

Investments	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investments	Investments (a) Available-For-Sale Debt Securities The amortized cost, gross unrealized gains and losses, and fair value on available-for-sale debt securities were as follows: March 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury $ 35,830 $ 860 $ (372 ) $ 36,318 Federal agencies 25,711 — (371 ) 25,340 States and political subdivision bonds 384,342 1,510 (7,595 ) 378,257 Foreign government 87,393 1,714 (28 ) 89,079 Corporate bonds 1,118,188 3,525 (22,890 ) 1,098,823 Residential mortgage-backed securities 1,052,632 566 (27,207 ) 1,025,991 Commercial mortgage-backed securities 229,624 593 (6,741 ) 223,476 Asset-backed securities 5,605 236 (103 ) 5,738 Structured securities 358,518 3,308 (528 ) 361,298 Total $ 3,297,843 $ 12,312 $ (65,835 ) $ 3,244,320 NGHC $ 2,981,076 $ 11,504 $ (59,000 ) $ 2,933,580 Reciprocal Exchanges 316,767 808 (6,835 ) 310,740 Total $ 3,297,843 $ 12,312 $ (65,835 ) $ 3,244,320 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury $ 36,236 $ 987 $ (230 ) $ 36,993 Federal agencies 20,711 5 (27 ) 20,689 States and political subdivision bonds 418,557 4,431 (3,907 ) 419,081 Foreign government 55,575 2,736 (57 ) 58,254 Corporate bonds 1,053,777 14,809 (7,697 ) 1,060,889 Residential mortgage-backed securities 1,020,481 211 (15,953 ) 1,004,739 Commercial mortgage-backed securities 143,519 2,340 (1,816 ) 144,043 Asset-backed securities 421 — (7 ) 414 Structured securities 390,514 4,959 (686 ) 394,787 Total $ 3,139,791 $ 30,478 $ (30,380 ) $ 3,139,889 NGHC $ 2,835,293 $ 27,117 $ (27,455 ) $ 2,834,955 Reciprocal Exchanges 304,498 3,361 (2,925 ) 304,934 Total $ 3,139,791 $ 30,478 $ (30,380 ) $ 3,139,889 As of March 31, 2018 and December 31, 2017 , the Company had no other-than-temporary impairments (“OTTI”) in AOCI related to available-for-sale debt securities. The amortized cost and fair value of available-for-sale debt securities held as of March 31, 2018 , by contractual maturity, are shown in the table below. Actual maturities may differ from contractual maturities because some borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. NGHC Reciprocal Exchanges Total March 31, 2018 Amortized Fair Amortized Fair Amortized Fair Due in one year or less $ 32,184 $ 31,994 $ 5,149 $ 5,182 $ 37,333 $ 37,176 Due after one year through five years 574,994 568,786 150,573 146,766 725,567 715,552 Due after five years through ten years 868,737 856,975 66,330 65,344 935,067 922,319 Due after ten years 297,644 299,553 14,371 14,515 312,015 314,068 Mortgage-backed securities 1,207,517 1,176,272 80,344 78,933 1,287,861 1,255,205 Total $ 2,981,076 $ 2,933,580 $ 316,767 $ 310,740 $ 3,297,843 $ 3,244,320 (b) Gross Unrealized Losses The tables below summarize the gross unrealized losses on debt securities classified as available for sale, by length of time the security has continuously been in an unrealized loss position. Less Than 12 Months 12 Months or More Total March 31, 2018 Fair Unrealized No. of Fair Unrealized No. of Fair Unrealized U.S. Treasury $ 20,464 $ (270 ) 131 $ 11,543 $ (102 ) 134 $ 32,007 $ (372 ) Federal agencies 24,738 (343 ) 15 602 (28 ) 4 25,340 (371 ) States and political subdivision bonds 192,758 (4,198 ) 302 82,744 (3,397 ) 119 275,502 (7,595 ) Foreign government 21,588 (28 ) 2 — — — 21,588 (28 ) Corporate bonds 726,521 (17,230 ) 738 109,865 (5,660 ) 96 836,386 (22,890 ) Residential mortgage-backed securities 890,769 (22,670 ) 99 84,388 (4,537 ) 7 975,157 (27,207 ) Commercial mortgage-backed securities 164,033 (5,987 ) 17 12,360 (754 ) 14 176,393 (6,741 ) Asset-backed securities 318 (47 ) 1 1,585 (56 ) 7 1,903 (103 ) Structured securities 52,459 (399 ) 34 6,022 (129 ) 3 58,481 (528 ) Total $ 2,093,648 $ (51,172 ) 1,339 $ 309,109 $ (14,663 ) 384 $ 2,402,757 $ (65,835 ) NGHC $ 1,857,583 $ (45,042 ) 1,203 $ 292,084 $ (13,958 ) 375 $ 2,149,667 $ (59,000 ) Reciprocal Exchanges 236,065 (6,130 ) 136 17,025 (705 ) 9 253,090 (6,835 ) Total $ 2,093,648 $ (51,172 ) 1,339 $ 309,109 $ (14,663 ) 384 $ 2,402,757 $ (65,835 ) Less Than 12 Months 12 Months or More Total December 31, 2017 Fair Unrealized No. of Fair Unrealized No. of Fair Unrealized U.S. Treasury $ 21,567 $ (131 ) 62 $ 10,555 $ (99 ) 20 $ 32,122 $ (230 ) Federal agencies 10,069 (11 ) 6 615 (16 ) 4 10,684 (27 ) States and political subdivision bonds 145,396 (1,851 ) 215 86,894 (2,056 ) 125 232,290 (3,907 ) Foreign government — — — 2,443 (57 ) 2 2,443 (57 ) Corporate bonds 402,236 (4,564 ) 341 110,207 (3,133 ) 93 512,443 (7,697 ) Residential mortgage-backed securities 886,032 (13,476 ) 72 89,412 (2,477 ) 9 975,444 (15,953 ) Commercial mortgage-backed securities 50,537 (727 ) 14 27,072 (1,089 ) 27 77,609 (1,816 ) Asset-backed securities — — — 414 (7 ) 2 414 (7 ) Structured securities 73,561 (631 ) 18 3,727 (55 ) 4 77,288 (686 ) Total $ 1,589,398 $ (21,391 ) 728 $ 331,339 $ (8,989 ) 286 $ 1,920,737 $ (30,380 ) NGHC $ 1,408,081 $ (19,254 ) 623 $ 300,732 $ (8,201 ) 268 $ 1,708,813 $ (27,455 ) Reciprocal Exchanges 181,317 (2,137 ) 105 30,607 (788 ) 18 211,924 (2,925 ) Total $ 1,589,398 $ (21,391 ) 728 $ 331,339 $ (8,989 ) 286 $ 1,920,737 $ (30,380 ) There were 1,723 and 1,014 securities at March 31, 2018 and December 31, 2017 , respectively, that account for the gross unrealized loss, none of which are deemed by the Company to be other-than-temporary impairments. Significant factors influencing the Company’s determination that none of these securities were OTTI included the length of time and/or magnitude of unrealized losses in relation to cost, the nature of the investment, the current financial condition of the issuer and its future prospects, the ability to recover to cost in the near term, and management’s intent not to sell these securities and it being more likely than not that the Company will not be required to sell these investments before anticipated recovery of fair value to the Company’s cost basis. As of March 31, 2018 and December 31, 2017 , of the $14,663 and $8,989 , respectively, of unrealized losses in unrealized loss positions for a period of twelve or more consecutive months, none of those were greater than or equal to 25% of its amortized cost. The Company regularly monitors its investments that have fair values less than cost or amortized cost for indicators of other-than-temporary impairment, an assessment that requires significant management judgment regarding the evidence known. Such judgments could change in the future as more information becomes known, which could negatively impact the amounts reported. (c) Equity Securities The fair values on equity securities were as follows: March 31, 2018 December 31, 2017 Common stock $ 47,993 $ 48,119 Preferred stock 2,164 2,222 Total $ 50,157 $ 50,341 NGHC $ 50,157 $ 50,341 Reciprocal Exchanges — — Total $ 50,157 $ 50,341 (d) Investment Income The components of net investment income consisted of the following: Three Months Ended March 31, 2018 2017 Cash and short-term investments $ 187 $ 34 Debt securities 24,256 26,818 Equity securities 155 75 Other income, net (related parties - $(295) and $3,814) 1,821 3,818 Investment income 26,419 30,745 Investment expenses (1,408 ) (1,701 ) Net Investment Income $ 25,011 $ 29,044 NGHC $ 22,867 $ 26,160 Reciprocal Exchanges 2,144 2,884 Net Investment Income $ 25,011 $ 29,044 (e) Net Realized Gains (Losses) Purchases and sales of investments are recorded on a trade date basis. Realized gains and losses are determined based on the specific identification method. The table below indicates realized gains and losses. Three Months Ended March 31, 2018 2017 Gross Gross Net Gains (Losses) Gross Gains Gross Losses Net Gains (Losses) Debt securities, available-for-sale $ 1,169 $ (1,171 ) $ (2 ) $ 2,487 $ (1,745 ) $ 742 Debt securities, trading — — — 6,902 (9,545 ) (2,643 ) Equity securities 725 (1,773 ) (1,048 ) 8,027 (8,187 ) (160 ) Foreign exchange and other investments, net 1,168 — 1,168 649 — 649 Net realized gain (loss) on investments $ 3,062 $ (2,944 ) $ 118 $ 18,065 $ (19,477 ) $ (1,412 ) NGHC $ 2,437 $ (2,188 ) $ 249 $ 18,065 $ (19,477 ) $ (1,412 ) Reciprocal Exchanges 625 (756 ) (131 ) — — — Net realized gain (loss) on investments $ 3,062 $ (2,944 ) $ 118 $ 18,065 $ (19,477 ) $ (1,412 ) Net gains and losses recognized during the reporting period on equity securities and debt securities classified as trading still held at the reporting date were as follows: Three Months Ended March 31, 2018 2017 Equity Equity Securities and Debt Securities Net losses recognized during the period $ (1,048 ) $ (5,662 ) Less: Net losses recognized during the period on securities sold during the period — (1,800 ) Net losses recognized during the reporting period on securities still held at the reporting date $ (1,048 ) $ (3,862 ) (f) Credit Quality of Investments The tables below summarize the credit quality of the Company’s debt securities and preferred stock securities, as rated by Standard & Poor’s. NGHC Reciprocal Exchanges March 31, 2018 Cost or Amortized Cost Fair Value Percentage Cost or Amortized Cost Fair Value Percentage U.S. Treasury $ 29,333 $ 29,801 1.0 % $ 6,497 $ 6,517 2.1 % AAA 281,886 282,501 9.6 % 13,245 12,846 4.1 % AA, AA+, AA- 1,438,345 1,401,862 47.8 % 126,409 124,086 39.9 % A, A+, A- 557,155 548,341 18.7 % 154,305 151,145 48.6 % BBB, BBB+, BBB- 570,184 568,001 19.3 % 10,278 10,115 3.3 % BB+ and lower 106,292 105,238 3.6 % 6,033 6,031 2.0 % Total $ 2,983,195 $ 2,935,744 100.0 % $ 316,767 $ 310,740 100.0 % NGHC Reciprocal Exchanges December 31, 2017 Cost or Fair Value Percentage Cost or Amortized Cost Fair Value Percentage U.S. Treasury $ 30,244 $ 31,026 1.1 % $ 5,992 $ 5,967 2.0 % AAA 255,132 259,506 9.1 % 29,540 28,961 9.5 % AA, AA+, AA- 1,399,287 1,382,191 48.7 % 133,250 133,316 43.7 % A, A+, A- 531,185 534,298 18.8 % 135,682 136,657 44.8 % BBB, BBB+, BBB- 574,456 581,406 20.5 % — — — % BB+ and lower 47,542 48,759 1.8 % 34 33 — % Total $ 2,837,846 $ 2,837,186 100.0 % $ 304,498 $ 304,934 100.0 % The tables below summarize the investment quality of the Company’s corporate bond holdings and industry concentrations. March 31, 2018 AAA AA+, A+,A,A- BBB+, BB+ or Fair % of Corporate Bonds: Financial Institutions 3.6 % 2.1 % 25.4 % 10.4 % 2.0 % $ 477,583 43.5 % Industrials 0.5 % 4.3 % 23.9 % 24.2 % 2.4 % 607,146 55.3 % Utilities/Other — % — % 1.1 % 0.1 % — % 14,094 1.2 % Total 4.1 % 6.4 % 50.4 % 34.7 % 4.4 % $ 1,098,823 100.0 % NGHC 3.7 % 2.3 % 36.6 % 33.8 % 4.4 % $ 888,297 80.8 % Reciprocal Exchanges 0.4 % 4.1 % 13.8 % 0.9 % — % 210,526 19.2 % Total 4.1 % 6.4 % 50.4 % 34.7 % 4.4 % $ 1,098,823 100.0 % December 31, 2017 AAA AA+, A+,A,A- BBB+, BB+ or Fair % of Corporate Bonds: Financial Institutions 2.9 % 7.8 % 31.7 % 11.9 % — % $ 575,746 54.3 % Industrials 0.7 % 3.0 % 16.9 % 21.8 % 0.5 % 454,764 42.9 % Utilities/Other — % — % 1.3 % 1.5 % — % 30,388 2.8 % Total 3.6 % 10.8 % 49.9 % 35.2 % 0.5 % $ 1,060,898 100.0 % NGHC 2.9 % 3.4 % 37.1 % 35.2 % 0.5 % $ 839,615 79.1 % Reciprocal Exchanges 0.7 % 7.4 % 12.8 % — % — % 221,283 20.9 % Total 3.6 % 10.8 % 49.9 % 35.2 % 0.5 % $ 1,060,898 100.0 % (g) Cash and Cash Equivalents, Restricted Cash and Restricted Investments The Company, in order to conduct business in certain states, is required to maintain letters of credit or assets on deposit to support state mandated regulatory requirements and certain third party agreements. The Company also utilizes trust accounts to collateralize business with its reinsurance counterparties. These assets held are primarily in the form of cash or certain high grade securities. The Company’s cash, cash equivalents, and restricted cash are as follows: March 31, 2018 December 31, 2017 Cash and cash equivalents $ 321,937 $ 292,282 Restricted cash and cash equivalents 56,116 65,202 Cash, cash equivalents and restricted cash $ 378,053 $ 357,484 The fair values of the Company’s restricted investments are as follows: March 31, 2018 December 31, 2017 State deposits, at fair value $ 76,083 $ 76,996 Restricted investments to trusts, at fair value 108,786 110,314 Total $ 184,869 $ 187,310 (h) Short-term and Other Investments Short-term investments consist of money market funds rated by Standard & Poor’s as AAA. The table below summarizes the composition of other investments: March 31, 2018 December 31, 2017 Equity method investments (related parties - $114,871 and $221,375) $ 149,883 $ 256,321 Note receivable - related party. See Note 13, "Related Party Transactions" 126,930 126,173 Long-term Certificates of Deposit (CDs), at cost 20,339 20,339 Investments, at fair value 11,050 10,791 Investments, at cost or amortized cost 7,668 7,668 Total $ 315,870 $ 421,292 Equity method investments represent limited liability companies and limited partnership investments in real estate. Investments at fair value, primarily represent the Company’s right to receive the excess servicing spread related to servicing rights, for which the Company has elected the fair value option with changes in fair value recorded in earnings. Investments at cost or amortized cost, represent limited partnerships, loans and trusts. The Company believes its exposure to risk associated with these investments is generally limited to the investment carrying amounts. The Company’s cost-method investments are assessed for impairment quarterly. No impairment losses were recorded for the three months ended March 31, 2018 and 2017 . Equity Method Investments - Related Parties The significant shareholder of the Company has an ownership interest in AmTrust Financial Services, Inc. (“AmTrust”) and ACP Re Ltd. (“ACP Re”). The following entities formed with related parties are considered by the Company to be VIEs, for which the Company is not the primary beneficiary. The Company accounts for these entities using the equity method of accounting. In determining whether it is the primary beneficiary of a VIE, the Company considered qualitative and quantitative factors, including, but not limited to, activities that most significantly impact the VIE’s economic performance and which party controls such activities. The Company does not have the ability to direct the activities that most significantly impact the VIE’s economic performance. The Company believes its exposure to risk associated with these investments is generally limited to the investment carrying amounts. LSC Entities The Company has a 50% ownership interest in two entities (collectively, the “LSC Entities”) formed for the purpose of acquiring life settlement contracts, with AmTrust owning the remaining 50%. The LSC Entities used the contributed capital to pay premiums and purchase policies. A life settlement contract is a contract between the owner of a life insurance policy and a third party who obtains the ownership and beneficiary rights of the underlying life insurance policy. The LSC Entities account for these life settlement contracts using the fair value method. On December 28, 2017 , the LSC Entities contributed 136 life settlement contracts to a limited partnership managed and operated by an unrelated third party. The consideration for the transaction included $217,831 cash (including an advance of $39,724 on future payments from the limited partnership) and the right to receive certain contingent earn-out payments. As of December 31, 2017 , the LSC Entities had a 30% non-controlling equity interest in the limited partnership and the carrying value of their investment in the limited partnership was $68,085 . As of March 31, 2018 and December 31, 2017 , the LSC Entities directly held five and six life settlement contracts, respectively. The Company’s equity interest in the LSC Entities as of March 31, 2018 and December 31, 2017 , was $56,348 and $160,683 , respectively. For the three months ended March 31, 2018 and 2017 , the Company recorded equity in earnings (losses) from the LSC Entities of $700 and $3,875 , respectively, made contributions of $2,000 and $10,000 , respectively, and received distributions of $107,035 and $0 , respectively. 800 Superior, LLC The Company holds an investment in 800 Superior, LLC, a limited liability company that owns an office building in Cleveland, Ohio, with AmTrust. AmTrust has been appointed managing member of 800 Superior, LLC. The Company and AmTrust each have a 50% ownership interest in 800 Superior, LLC. Additionally, the Company entered into an office lease with 800 Superior, LLC. The Company paid 800 Superior, LLC $722 and $703 in rent for the three months ended March 31, 2018 and 2017 , respectively. The Company’s equity interest in 800 Superior, LLC as of March 31, 2018 and December 31, 2017 was $335 and $1,405 , respectively. For the three months ended March 31, 2018 and 2017 , the Company recorded equity in earnings (losses) from 800 Superior, LLC of $(1,070) and $(117) , respectively. East Ninth & Superior, LLC The Company holds an investment in East Ninth & Superior, LLC and 800 Superior NMTC Investment Fund II, LLC with AmTrust (collectively “East Ninth & Superior”). The Company and AmTrust each have a 50% ownership interest in East Ninth and Superior, LLC and a 24.5% ownership interest in 800 Superior NMTC Investment Fund II, LLC. The Company’s equity interest in East Ninth & Superior as of March 31, 2018 and December 31, 2017 was $4,267 and $4,251 , respectively. For the three months ended March 31, 2018 and 2017 , the Company recorded equity in earnings (losses) from East Ninth & Superior of $16 and $10 , respectively. North Dearborn Building Company, L.P. The Company holds an investment in North Dearborn Building Company, L.P. (“North Dearborn”), a limited partnership that owns an office building in Chicago, Illinois. AmTrust is also a limited partner in North Dearborn, and the general partner is NA Advisors GP LLC (“NA Advisors”), a related party, owned by Karfunkel family members which is managed by an unrelated third party. The Company and AmTrust each hold a 45% limited partnership interest in North Dearborn, while NA Advisors holds a 10% general partnership interest and a 10% profit interest, which NA Advisors pays to the unrelated third party manager. North Dearborn appointed NA Advisors as the general manager to oversee the day-to-day operations of the office building. The Company’s equity interest in North Dearborn as of March 31, 2018 and December 31, 2017 was $7,573 and $7,582 , respectively. For the three months ended March 31, 2018 and 2017 , the Company recorded equity in earnings (losses) from North Dearborn of $(9) and $(250) , respectively. 4455 LBJ Freeway, LLC The Company holds an investment in 4455 LBJ Freeway, LLC, a limited liability company that owns an office building in Dallas, Texas, with AmTrust. AmTrust has been appointed managing member of 4455 LBJ Freeway, LLC. The Company and AmTrust each have a 50% ownership interest in 4455 LBJ Freeway, LLC. Additionally, the Company entered into a lease agreement with 4455 LBJ Freeway, LLC. The Company paid 4455 LBJ Freeway, LLC $574 and $424 in rent for the three months ended March 31, 2018 and 2017 , respectively. The Company’s equity interest in 4455 LBJ Freeway, LLC as of March 31, 2018 and December 31, 2017 was $742 and $740 , respectively. For the three months ended March 31, 2018 and 2017 , the Company recorded equity in earnings (losses) from 4455 LBJ Freeway, LLC of $2 and $125 , respectively. Illinois Center Building, L.P. The Company holds an investment in Illinois Center Building, L.P. (“Illinois Center”), a limited partnership that owns an office building in Chicago, Illinois. AmTrust and ACP Re are also limited partners in Illinois Center and the general partner is NA Advisors. The Company and AmTrust each hold a 37.5% limited partnership interest in Illinois Center, while ACP Re holds a 15.0% limited partnership interest. NA Advisors holds a 10.0% general partnership interest and a 10.0% profit interest, which NA Advisors pays to the unrelated third party manager. Illinois Center appointed NA Advisors as the general manager to oversee the day-to-day operations of the office building. The Company’s equity interest in Illinois Center as of March 31, 2018 and December 31, 2017 was $45,606 and $46,715 , respectively. For the three months ended March 31, 2018 and 2017 , the Company recorded equity in earnings (losses) from Illinois Center of $(1,109) and $(1,163) , respectively.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company carries certain financial instruments at fair value. Assets and liabilities recorded at fair value in the condensed consolidated balance sheets are measured and classified in accordance with a fair value hierarchy consisting of three “levels” based on the observability of valuation inputs: Level 1 - Inputs are quoted prices in active markets for identical assets or liabilities as of the measurement date. Additionally, the entity must have the ability to access the active market and the quoted prices cannot be adjusted by the entity. Level 2 - Inputs are other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices in active markets for similar assets or liabilities; quoted prices in inactive markets for identical or similar assets or liabilities; or inputs that are observable or can be corroborated by observable market data by correlation or other means for substantially the full term of the assets or liabilities. Level 3 - Unobservable inputs are supported by little or no market activity. The unobservable inputs represent management’s best assumptions of how market participants would price the assets or liabilities. Generally, Level 3 assets and liabilities are valued using pricing models, discounted cash flow methodologies, or similar techniques that require significant judgment or estimation. The following describes the valuation techniques used by the Company to determine the fair value measurements on a recurring basis of financial instruments held as of March 31, 2018 and December 31, 2017 . The Company utilizes a pricing service (“pricing service”) to estimate fair value measurements for all its debt and equity securities. Level 1 measurements: • U.S. Treasury and federal agencies. The fair values of U.S. government securities are based on quoted market prices in active markets. The Company believes the market for U.S. government securities is an actively traded market given the high level of daily trading volume. • Common stock. The pricing service utilizes market quotations for equity securities that have quoted market prices in active markets and their respective quoted prices are provided at fair value. • Short-term investments. Comprised of money market funds that are traded in active markets and fair values are based on quoted market prices. Level 2 measurements: • States and political subdivision bonds, and foreign government. The primary inputs to the valuation include quoted prices for identical or similar assets in markets that are not active. • Corporate bonds. Comprised of bonds issued by corporations, public and privately placed. The fair values of short-term corporate bonds are priced using the spread above the London Interbank Offering Rate (“LIBOR”) yield curve, and the fair value of long-term corporate bonds are priced using the spread above the risk-free yield curve. The spreads are sourced from broker dealers, trade prices and the new issue market. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers. The primary inputs to the valuation include quoted prices for identical or similar assets in markets that are not active. • Residential and commercial mortgage-backed securities, asset-backed securities and structured securities. The primary inputs to the valuation include quoted prices for identical or similar assets in markets that are not active, contractual cash flows, benchmark yields, prepayment speeds, collateral performance and credit spreads. • Preferred stock. The pricing service also provides fair value estimates for certain equity securities whose fair value is based on observable market information rather than market quotes. Level 3 measurements: • States and political subdivision bonds. The Company holds certain municipal bonds that finance economic development, infrastructure and environmental projects which do not have an active market. These bonds are valued based on non-binding broker quotes where the inputs have not been corroborated to be market observable. • Foreign government bonds. The Company holds certain foreign government bonds that are valued based on non-binding broker quotes where the inputs have not been corroborated to be market observable. • Corporate bonds. The Company holds certain structured notes and term loans that do not have an active market. These bonds are valued based on non-binding broker quotes where the inputs have not been corroborated to be market observable. • Residential and commercial mortgage-backed securities and structured securities. The Company holds certain mortgage and structured securities valued based on non-binding broker quotes received from brokers who are familiar with the investments and where the inputs have not been corroborated to be market observable. • Common stock and preferred stock. From time to time, the Company also holds certain equity securities that are issued by privately-held entities or direct equity investments that do not have an active market. The Company estimates the fair value of these securities primarily based on inputs such as third-party broker quotes, issuers’ book value, market multiples, and other inputs. These bonds are valued based on non-binding broker quotes where the inputs have not been corroborated to be market observable. • Other investments, at fair value. Comprised of the Company’s right to receive the Excess Servicing Spread (“ESS”) related to servicing rights. The Company uses a discounted cash flow method to estimate their fair value. The key inputs used in the estimation of ESS include prepayment speed and discount rate. Changes in the fair value of the ESS are recorded in earnings. Assets measured at fair value on a recurring basis are as follows: March 31, 2018 Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Available-for-sale debt securities: U.S. Treasury $ 36,318 $ — $ — $ 36,318 Federal agencies 25,340 — — 25,340 States and political subdivision bonds — 374,130 4,127 378,257 Foreign government — 89,079 — 89,079 Corporate bonds — 1,074,310 24,513 1,098,823 Residential mortgage-backed securities — 1,025,991 — 1,025,991 Commercial mortgage-backed securities — 223,476 — 223,476 Asset-backed securities — 5,738 — 5,738 Structured securities — 361,298 — 361,298 Total available-for-sale debt securities 61,658 3,154,022 28,640 3,244,320 Equity securities: Common stock 44,127 — 3,866 47,993 Preferred stock — 1,882 282 2,164 Total equity securities 44,127 1,882 4,148 50,157 Short-term investments 39,969 — — 39,969 Other investments — — 11,050 11,050 Total $ 145,754 $ 3,155,904 $ 43,838 $ 3,345,496 NGHC $ 117,412 $ 2,851,681 $ 43,838 $ 3,012,931 Reciprocal Exchanges 28,342 304,223 — 332,565 Total $ 145,754 $ 3,155,904 $ 43,838 $ 3,345,496 December 31, 2017 Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Available-for-sale debt securities: U.S. Treasury $ 36,993 $ — $ — $ 36,993 Federal agencies 20,689 — — 20,689 States and political subdivision bonds — 415,000 4,081 419,081 Foreign government — 58,254 — 58,254 Corporate bonds — 1,036,344 24,545 1,060,889 Residential mortgage-backed securities — 1,004,739 — 1,004,739 Commercial mortgage-backed securities — 144,043 — 144,043 Asset-backed securities — 414 — 414 Structured securities — 394,787 — 394,787 Total available-for-sale debt securities 57,682 3,053,581 28,626 3,139,889 Equity securities: Common stock 43,067 — 5,052 48,119 Preferred stock — 1,952 270 2,222 Total equity securities 43,067 1,952 5,322 50,341 Short-term investments 38,266 — — 38,266 Other investments — 9 10,782 10,791 Total $ 139,015 $ 3,055,542 $ 44,730 $ 3,239,287 NGHC $ 110,769 $ 2,756,575 $ 44,730 $ 2,912,074 Reciprocal Exchanges 28,246 298,967 — 327,213 Total $ 139,015 $ 3,055,542 $ 44,730 $ 3,239,287 The following tables provide a reconciliation of recurring fair value measurements of the Company’s Level 3 financial assets: Total gains (losses) included in: Balance as of January 1, 2018 Net Other Purchases Sales Net transfers Balance as of March 31, 2018 Net gains (losses) included in net income on instruments held at end of period States and political subdivision bonds $ 4,081 $ — $ 46 $ — $ — $ — $ 4,127 $ — Corporate bonds 24,545 — (32 ) — — — 24,513 — Common stock 5,052 (1,186 ) — — — — 3,866 (1,186 ) Preferred stock 270 12 — — — — 282 12 Other investments (1) 10,782 794 — — (526 ) — 11,050 794 Total $ 44,730 $ (380 ) $ 14 $ — $ (526 ) $ — $ 43,838 $ (380 ) Total gains (losses) included in: Balance as of January 1, 2017 Net Other Purchases Sales Net transfers Balance as of March 31, 2017 Net gains (losses) included in net income on instruments held at end of period States and political subdivision bonds $ 4,732 $ — $ — $ — $ — $ (4,732 ) $ — $ — Foreign government 1,910 — — — — (1,910 ) — — Corporate bonds 36,044 — 530 — (9,620 ) 287 27,241 — Residential mortgage-backed securities 7,423 — — — — (7,422 ) 1 — Commercial mortgage-backed securities 4,849 — — — — (4,849 ) — — Structured securities 9,055 — — — — (7,054 ) 2,001 — Common stock 6,297 — — 4,119 (6,297 ) 1 4,120 — Preferred stock — — — — — 280 280 — Other investments (1) 9,427 184 — 3,986 (755 ) — 12,842 184 Total $ 79,737 $ 184 $ 530 $ 8,105 $ (16,672 ) $ (25,399 ) $ 46,485 $ 184 (1) Other investments gains and losses recognized in net income are reported within net investment income in the condensed consolidated statements of income. During the three months ended March 31, 2018 , there were no transfers between Level 1 and Level 2 or between Level 2 and Level 3. During the three months ended March 31, 2017 , there were no transfers between Level 1 and Level 2. During the three months ended March 31, 2017 , the Company transferred $31,917 out of Level 3 into Level 2, due to changes in broker quotes where the inputs included quoted prices for identical or similar assets in markets that are not active resulting in the securities being classified as Level 2; and $6,518 out of Level 2 into Level 3, due to changes in broker quotes where the inputs had not been corroborated to be market observable resulting in the securities being classified as Level 3. The Company’s policy is to recognize transfers between levels as of the end of each reporting period, consistent with the date of determination of fair value. At March 31, 2018 and December 31, 2017 , the carrying values of the Company’s short-term investments, cash and cash equivalents, premiums and other receivables, and accounts payable approximate the fair value given their short-term nature and are classified as Level 1. Fair value information about financial instruments not measured at fair value Debt - The amount reported in the accompanying condensed consolidated balance sheets for these financial instruments represents the carrying value of the debt. See Note 9 , “ Debt ” for additional information. The Company’s 7.625% Notes are publicly traded and classified as Level 2. The Company’s 6.75% Notes, the Subordinated Debentures, the Imperial Surplus Notes, the SPCIC Surplus Notes and the Credit Agreement are not publicly traded and are classified as Level 3. As of March 31, 2018 and December 31, 2017 , the fair values of the Company’s 6.75% Notes and the Credit Agreement were determined using analytical procedures on similar publicly traded corporate bonds and loans, and were valued using the discounted cash flow method of the income approach. The cash flows were discounted at a market yield, calculated using the risk-free rate plus a credit spread. As of March 31, 2018 and December 31, 2017 , the fair values of the Company’s Subordinated Debentures, Imperial Surplus Notes and SPCIC Surplus Notes were valued using the Black-Derman-Toy interest rate lattice model. The following table presents the carrying amount and fair value estimates of debt not carried at fair value: March 31, 2018 December 31, 2017 Carrying amount Fair value Carrying amount Fair value 7.625% Notes $ 96,778 $ 99,226 $ 96,756 $ 101,640 6.75% Notes 345,947 362,828 345,786 366,131 Subordinated Debentures 72,168 72,084 72,168 72,101 Imperial Surplus Notes 5,000 4,984 5,000 4,984 SPCIC Surplus Notes 4,000 3,995 4,000 3,996 Credit Agreement 190,000 194,167 190,000 195,420 Total $ 713,893 $ 737,284 $ 713,710 $ 744,272

Deferred Acquisition Costs

Deferred Acquisition Costs	3 Months Ended
	Mar. 31, 2018
Deferred Acquisition Costs [Abstract]
Deferred Policy Acquisition Costs	Deferred Acquisition Costs The following table reflects the amounts of policy acquisition costs deferred and amortized: Three Months Ended March 31, 2018 2017 Property Accident Total Property Accident Total Balance at beginning of the period $ 198,283 $ 18,106 $ 216,389 $ 207,597 $ 13,325 $ 220,922 Additions 139,132 5,940 145,072 155,535 21,121 176,656 Amortization (120,332 ) (7,529 ) (127,861 ) (135,114 ) (19,680 ) (154,794 ) Change in DAC 18,800 (1,589 ) 17,211 20,421 1,441 21,862 Balance at end of the period $ 217,083 $ 16,517 $ 233,600 $ 228,018 $ 14,766 $ 242,784 NGHC $ 195,448 $ 16,517 $ 211,965 $ 194,740 $ 14,766 $ 209,506 Reciprocal Exchanges 21,635 — 21,635 33,278 — 33,278 Balance at end of the period $ 217,083 $ 16,517 $ 233,600 $ 228,018 $ 14,766 $ 242,784

Unpaid Losses and Loss Adjustme

Unpaid Losses and Loss Adjustment Expense Reserves	3 Months Ended
	Mar. 31, 2018
Insurance [Abstract]
Unpaid Losses and Loss Adjustment Expenses	Unpaid Losses and Loss Adjustment Expense Reserves The unpaid losses and loss adjustment expense (“LAE”) reserves are the result of ongoing analysis of recent loss development trends and emerging historical experience. Original estimates are increased or decreased as additional information becomes known regarding individual claims. In setting its reserves, the Company reviews its loss data to estimate expected loss development. Management believes that its use of standard actuarial methodology applied to its analyses of its historical experience provides a reasonable estimate of future losses. However, actual future losses may differ from the Company’s estimate, and future events beyond the control of management, such as changes in law, judicial interpretations of law and inflation, may favorably or unfavorably impact the ultimate settlement of the Company’s losses and LAE. The anticipated effect of inflation is implicitly considered when estimating liabilities for losses and LAE. In addition to inflation, the average severity of claims is affected by a number of factors that may vary by types and features of policies written. Future average severities are projected from historical trends, adjusted for implemented changes in underwriting standards and policy provisions, and general economic trends. These estimated trends are monitored and revised as necessary based on actual development. The table below shows the rollforward of loss reserves on a gross and net of reinsurance basis, reflecting changes in losses incurred and paid losses: Three Months Ended March 31, 2018 2017 Property Accident NGHC Reciprocal Total Property Accident NGHC Reciprocal Total Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period $ 2,270,551 $ 249,653 $ 2,520,204 $ 143,353 $ 2,663,557 $ 1,936,391 $ 200,400 $ 2,136,791 $ 137,075 $ 2,273,866 Less: Reinsurance recoverables at beginning of the period (1,067,495 ) (9,840 ) (1,077,335 ) (52,408 ) (1,129,743 ) (827,672 ) (10,933 ) (838,605 ) (42,192 ) (880,797 ) Net balance at beginning of the period 1,203,056 239,813 1,442,869 90,945 1,533,814 1,108,719 189,467 1,298,186 94,883 1,393,069 Incurred losses and LAE related to: Current year 513,526 94,661 608,187 45,917 654,104 525,688 77,703 603,391 30,020 633,411 Prior year (15,169 ) (3,383 ) (18,552 ) (1,386 ) (19,938 ) (4,354 ) (8,320 ) (12,674 ) (1,920 ) (14,594 ) Total incurred 498,357 91,278 589,635 44,531 634,166 521,334 69,383 590,717 28,100 618,817 Paid losses and LAE related to: Current year (202,967 ) (20,290 ) (223,257 ) (19,686 ) (242,943 ) (165,950 ) (14,568 ) (180,518 ) (12,886 ) (193,404 ) Prior year (306,126 ) (47,992 ) (354,118 ) (17,455 ) (371,573 ) (347,864 ) (51,432 ) (399,296 ) (15,246 ) (414,542 ) Total paid (509,093 ) (68,282 ) (577,375 ) (37,141 ) (614,516 ) (513,814 ) (66,000 ) (579,814 ) (28,132 ) (607,946 ) Effect of foreign exchange rates — (1,679 ) (1,679 ) — (1,679 ) — 1,043 1,043 — 1,043 Net balance at end of the period 1,192,320 261,130 1,453,450 98,335 1,551,785 1,116,239 193,893 1,310,132 94,851 1,404,983 Plus reinsurance recoverables at end of the period 1,058,106 8,565 1,066,671 60,461 1,127,132 819,538 10,732 830,270 44,234 874,504 Gross balance at end of period $ 2,250,426 $ 269,695 $ 2,520,121 $ 158,796 $ 2,678,917 $ 1,935,777 $ 204,625 $ 2,140,402 $ 139,085 $ 2,279,487 Prior year loss development, net of reinsurance Prior year development is based upon numerous estimates by line of business and accident year. No additional premiums or return premiums have been accrued as a result of the prior year effects. 2018 . Loss and LAE for the three months ended March 31, 2018 included $19,938 of favorable development on prior accident year loss and LAE reserves. The $16,555 of favorable development in the property and casualty business (including $1,386 of favorable development for the Reciprocal Exchanges) was driven by favorable development in the Company’s auto physical damage and homeowners business, while the $3,383 of favorable development in the accident and health business was primarily driven by favorable development in the Company’s domestic business. 2017 . Loss and LAE for the three months ended March 31, 2017 included $14,594 of favorable development on prior accident year loss and LAE reserves. The $6,274 of favorable development in the property and casualty business (including $1,920 of favorable development for the Reciprocal Exchanges) was primarily driven by favorable development in the Company’s homeowners business which was partially offset by unfavorable development in private passenger auto bodily injury coverage, while $8,320 of favorable development in the accident and health business was primarily driven by favorable development in the Company’s domestic stop loss programs.

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2018
Insurance [Abstract]
Reinsurance	Reinsurance The Company’s insurance subsidiaries utilize reinsurance agreements to transfer portions of the underlying risk of the business the Company writes to various affiliated and third-party reinsurance companies. Reinsurance does not discharge or diminish the Company’s obligation to pay claims covered by the insurance policies it issues; however, it does permit the Company to recover certain incurred losses from its reinsurers and the Company’s reinsurance recoveries reduce the maximum loss that it may incur as a result of a covered loss event. The Company’s reinsurers generally carry at least an A.M. Best Company, Inc. rating of “A-” (Excellent) or are fully collateralized at the time they enter into the Company’s reinsurance agreements. The Company also enters reinsurance relationships with third-party captives formed by agents as a mechanism for sharing risk and profit. The total amount, cost and limits relating to the reinsurance coverage the Company purchases may vary from year to year based upon a variety of factors, including the availability of quality reinsurance at an acceptable price and the level of risk that the Company chooses to retain for its own account. The Company assumes and cedes insurance risks under various reinsurance agreements, on both a pro rata basis and excess of loss basis. The Company purchases reinsurance to mitigate the volatility of direct and assumed business, which may be caused by the aggregate value or the concentration of written exposures in a particular geographic area or business segment and may arise from catastrophes or other events. The Company pays a premium as consideration for ceding the risk. The following is the effect of reinsurance on unpaid loss and LAE reserves and unearned premiums: March 31, 2018 December 31, 2017 Assumed Ceded Assumed Ceded Unpaid Loss and LAE reserves $ 106,476 $ 1,127,132 $ 134,246 $ 1,129,743 Unearned premiums 35,385 528,770 45,182 517,122 The following is a summary of the effect of reinsurance on premiums and losses: Three Months Ended March 31, 2018 2017 Written Earned Written Earned Premium: Direct $ 1,413,877 $ 1,191,327 $ 1,195,221 $ 935,775 Assumed 19,253 29,051 58,162 98,038 Total Gross Premium 1,433,130 1,220,378 1,253,383 1,033,813 Ceded (326,487 ) (314,840 ) (128,330 ) (115,328 ) Net Premium $ 1,106,643 $ 905,538 $ 1,125,053 $ 918,485 Three Months Ended March 31, 2018 2017 Assumed Ceded Assumed Ceded Loss and LAE $ (1,321 ) $ 197,317 $ 29,946 $ 91,552 Quota Share Agreements Effective July 1, 2017 , the Company entered into an Auto Quota Share Agreement (the “Auto Quota Share Agreement”) covering the Company’s auto lines of business, under which the Company cedes 15.0% of net liability under auto policies in force as of the effective date and new and renewal policies issued during the two -year term of the agreement to an unaffiliated third-party reinsurance provider. Under the Auto Quota Share Agreement, the Company receives a 31.2% provisional ceding commission on premiums ceded to the reinsurer during the term of the Auto Quota Share Agreement, subject to a sliding scale adjustment to a maximum of 32.8% if the loss ratio for the reinsured business is 63.4% or less and a minimum of 29.6% if the loss ratio is 66.6% or higher. The liability of the reinsurer is capped at $5,000 per risk or $70,000 per event. The cession may be increased, under certain conditions, up to a maximum cession of 20.0% . Effective July 1, 2017 , the Company entered into a Homeowners Quota Share Agreement (the “HO Quota Share Agreement”) covering the Company’s homeowners line of business, under which the Company cedes 29.6% of net liability under homeowners policies, including lender-placed property policies, in force as of the effective date and new and renewal policies issued during the two -year term of the agreement to unaffiliated third-party reinsurance providers. Under the HO Quota Share Agreement, the Company receives a 42.5% ceding commission on premiums ceded to the reinsurers during the term of the HO Quota Share Agreement. The liability of the reinsurers is capped at $5,000 per risk or $70,000 per event. Effective May 1, 2018 , the Company cedes an additional 12.4% of net liability (for a total cession of 42.0% ) and receives a 38.0% ceding commission on the additional 12.4% in ceded premiums. Catastrophe Reinsurance As of May 1, 2017 , the Company’s reinsurance property catastrophe excess of loss program went into effect protecting the Company against catastrophic events and other large losses. The property catastrophe program provides a total of $575,000 in coverage in excess of a $70,000 retention, with one reinstatement. Effective July 1, 2017 , the casualty program provides $45,000 in coverage in excess of a $5,000 retention. The Company pays a premium as consideration for ceding the risk. The Company renewed its property catastrophe excess of loss program under the same coverages effective May 1, 2018 . As of July 1, 2017 , a reinsurance property catastrophe excess of loss program went into effect protecting the Reciprocal Exchanges against accumulations of losses resulting from a catastrophic event. The property catastrophe program provides a total of $375,000 in coverage in excess of a $20,000 retention, with one reinstatement.

Debt

Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Debt	Debt 7.625% Subordinated Notes due 2055 The Company previously issued $100,000 aggregate principal amount of the Company’s 7.625% subordinated notes due 2055 (the “ 7.625% Notes”) in a public offering. The net proceeds the Company received from the issuance were approximately $96,550 , after deducting the underwriting discount, commissions and expenses. The 7.625% Notes bear interest at a rate equal to 7.625% per year, payable quarterly in arrears on March 15, June 15, September 15 and December 15 of each year. The 7.625% Notes are the Company’s subordinated unsecured obligations and rank (i) senior in right of payment to any future junior subordinated debt, (ii) equal in right of payment with any unsecured, subordinated debt that the Company incurs in the future that ranks equally with the 7.625% Notes, and (iii) subordinate in right of payment to any of the Company’s existing and future senior debt, including amounts outstanding under the Company’s revolving credit facility, the Company’s 6.75% notes and certain of the Company’s other obligations. In addition, the 7.625% Notes are structurally subordinated to all existing and future indebtedness, liabilities and other obligations of the Company’s subsidiaries. The 7.625% Notes mature on September 15, 2055, unless earlier redeemed or purchased by the Company. Interest expense on the 7.625% Notes for the three months ended March 31, 2018 and 2017 , was $1,906 and $1,880 , respectively. The indenture contains customary covenants, such as reporting of annual and quarterly financial results, and restrictions on certain mergers and consolidations. The indenture also includes covenants relating to the incurrence of debt if the Company’s consolidated leverage ratio would exceed 0.35 to 1.00 , a limitation on liens, a limitation on the disposition of stock of certain of the Company’s subsidiaries and a limitation on transactions with certain of the Company’s affiliates. The Company was in compliance with all of the covenants contained in the indenture as of March 31, 2018 . 6.75% Notes due 2024 The Company previously issued $350,000 aggregate principal amount of the Company’s 6.75% notes due 2024 (the “ 6.75% Notes”) to certain purchasers in two private placements. The net proceeds the Company received from the issuances were approximately $343,850 , after deducting issuance expenses. The 6.75% Notes bear interest at a rate equal to 6.75% per year, payable semiannually in arrears on May 15 and November 15 of each year. The 6.75% Notes are the Company’s general unsecured obligations and rank equally in right of payment with its other existing and future senior unsecured indebtedness and senior in right of payment to any of its indebtedness that is contractually subordinated to the 6.75% Notes. The 6.75% Notes are also effectively subordinated to any of the Company’s existing and future secured indebtedness to the extent of the value of the collateral securing such indebtedness and are structurally subordinated to the existing and future indebtedness of the Company’s subsidiaries (including trade payables). The 6.75% Notes mature on May 15, 2024, unless earlier redeemed or purchased by the Company. Interest expense on the 6.75% Notes for the three months ended March 31, 2018 and 2017 , was $5,906 and $5,825 , respectively. The indenture contains customary covenants, such as reporting of annual and quarterly financial results, and restrictions on certain mergers and consolidations. The indenture also includes covenants relating to the incurrence of debt if the Company’s consolidated leverage ratio would exceed 0.35 to 1.00 , a limitation on liens, a limitation on the disposition of stock of certain of the Company’s subsidiaries and a limitation on transactions with certain of the Company’s affiliates. The Company was in compliance with all of the covenants contained in the indenture as of March 31, 2018 . Subordinated Debentures The Company’s subsidiary, Direct General Corporation, is the issuer of junior subordinated debentures (the “Subordinated Debentures”) relating to an issuance of trust preferred securities. The Subordinated Debentures require interest-only payments to be made on a quarterly basis, with principal due at maturity. The Subordinated Debentures’ principal amounts of $41,238 and $30,930 mature on 2035 and 2037 , respectively, and bear interest at an annual rate equal to LIBOR plus 3.40% and LIBOR plus 4.25% , respectively. The Subordinated Debentures are redeemable by the Company at a redemption price equal to 100% of their principal amount. Interest expense on the Subordinated Debentures for the three months ended March 31, 2018 and 2017 , was $986 and $1,003 , respectively. Imperial-related Debt The Company’s subsidiary, Imperial Fire and Casualty Insurance Company, is the issuer of $5,000 principal amount of Surplus Notes due 2034 (“Imperial Surplus Notes”). The notes bear interest at an annual rate equal to LIBOR plus 4.05% , payable quarterly. The notes are redeemable by the Company at a redemption price equal to 100% of their principal amount. Interest expense on the Imperial Surplus Notes for the three months ended March 31, 2018 and 2017 , was $71 and $63 , respectively. SPCIC-related Debt The Company’s subsidiary, Standard Property and Casualty Insurance Company, is the issuer of $4,000 principal amount of Surplus Notes due 2033 (“SPCIC Surplus Notes”). The notes bear interest at an annual rate equal to LIBOR plus 4.15% , payable quarterly. The notes are redeemable by the Company at a redemption price equal to 100% of their principal amount. On April 2, 2018 , the Company redeemed the SPCIC Surplus Notes. Interest expense on the SPCIC Surplus Notes for the three months ended March 31, 2018 and 2017 , was $58 and $51 , respectively. Revolving Credit Agreement On January 25, 2016 , the Company entered into a credit agreement (the “Credit Agreement”), among JPMorgan Chase Bank, N.A., as Administrative Agent, KeyBank National Association as Syndication Agent, and Associated Bank, National Association and First Niagara Bank, N.A., as Co-Documentation Agents, and the various lending institutions party thereto. The credit facility is a $245,000 base revolving credit facility with a letter of credit sublimit of $112,500 and an expansion feature not to exceed $50,000 . Proceeds of borrowings under the Credit Agreement may be used for working capital, acquisitions and general corporate purposes. The Credit Agreement has a maturity date of January 25, 2020 . The Credit Agreement contains certain restrictive covenants customary for facilities of this type (subject to negotiated exceptions and baskets), including restrictions on indebtedness, liens, acquisitions and investments, restricted payments and dispositions. There are also financial covenants that require the Company to maintain a minimum consolidated net worth, a maximum consolidated leverage ratio, a minimum fixed charge coverage ratio, a minimum risk-based capital and a minimum statutory surplus. The Credit Agreement also provides for customary events of default, with grace periods where customary, including failure to pay principal when due, failure to pay interest or fees within three business days after becoming due, failure to comply with covenants, breaches of representations and warranties, default under certain other indebtedness, certain insolvency or receivership events affecting the Company and its subsidiaries, the occurrence of certain material judgments, or a change in control of the Company. Upon the occurrence and during the continuation of an event of default, the administrative agent, upon the request of the requisite percentage of the lenders, may terminate the obligations of the lenders to make loans and to issue letters of credit under the Credit Agreement, declare the Company’s obligations under the Credit Agreement to become immediately due and payable and/or exercise any and all remedies and other rights under the Credit Agreement. Borrowings under the Credit Agreement bear interest at either the Alternate Base Rate (“ABR”) or LIBOR. ABR borrowings (which are borrowings bearing interest at a rate determined by reference to the ABR) under the Credit Agreement will bear interest at the greatest of (a) the prime rate in effect on such day, (b) the federal funds effective rate on such day plus 0.5 percent or (c) the adjusted LIBOR for a one-month interest period on such day plus 1 percent . Eurodollar borrowings under the Credit Agreement will bear interest at the adjusted LIBOR for the interest period in effect. Fees payable by the Company under the Credit Agreement include a letter of credit participation fee (the margin applicable to Eurodollar borrowings), a letter of credit fronting fee with respect to each letter of credit ( 0.125% ) and a commitment fee on the available commitments of the lenders (a range of 0.20% to 0.30% based on the Company’s consolidated leverage ratio, and which rate was 0.30% as of March 31, 2018 ). As of March 31, 2018 , there was $190,000 outstanding under the Credit Agreement. The weighted average interest rate on the amount outstanding as of March 31, 2018 was 4.23% . Interest payments are due the last day of the interest period in intervals of three months duration, commencing on the date of such borrowing. Interest expense on the Credit Agreement for the three months ended March 31, 2018 and 2017 , was $1,684 and $439 , respectively. The Company was in compliance with all of the covenants under the Credit Agreement as of March 31, 2018 . Maturities of the Company’s debt for the years subsequent to March 31, 2018 are as follows: 2018 (remaining nine months) 2019 2020 2021 2022 2023 Thereafter Total 7.625% Notes $ — $ — $ — $ — $ — $ — $ 100,000 $ 100,000 6.75% Notes — — — — — — 350,000 350,000 Subordinated Debentures — — — — — — 72,168 72,168 Imperial Surplus Notes — — — — — — 5,000 5,000 SPCIC Surplus Notes — — — — — — 4,000 4,000 Credit Agreement — — 190,000 — — — — 190,000 Total principal amount of debt $ — $ — $ 190,000 $ — $ — $ — $ 531,168 $ 721,168 Less: Unamortized debt issuance costs and unamortized discount (7,275 ) Carrying amount of debt $ 713,893

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company files a consolidated federal income tax return. The Reciprocal Exchanges are not included in the Company’s consolidated tax return as the Company does not have an ownership interest in the Reciprocal Exchanges, and they are not a part of the consolidated tax sharing agreement. The Tax Cuts and Jobs Act was enacted on December 22, 2017 (the “Act”). The Act reduces the U.S. federal corporate tax rate from 35% to 21% , requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred, creates new taxes on certain foreign sourced earnings, and revises the tax treatment of certain items for property and casualty insurers. As of March 31, 2018 , the Company has not completed the accounting for the tax effects of enactment of the Act and additional information and analysis is required; however, under the guidance, Staff Accounting Bulletin No. 118 (“SAB 118”), in certain cases, as described below, the Company has made a reasonable estimate of the effects on the existing deferred tax balances. For the items for which the Company was able to determine a reasonable estimate, the Company recognized a provisional expense (benefit) of $25,783 for NGHC and $(5,194) for the Reciprocal Exchanges during 2017. These amounts are primarily related to the restatement of deferred taxes from 35% to the newly enacted 2018 rate of 21% , and were recorded to income tax expense for the year ended December 31, 2017. No changes to these provisional amounts were recorded during the three months ended March 31, 2018 . The Company will continue to make and refine calculations as additional analysis is completed. In addition, the Company’s estimates may also be affected as the Company gains a more thorough understanding of the tax law and/or as regulations are promulgated. The Company uses the estimated annual effective tax rate method. Certain items, including those deemed to be unusual, infrequent or that cannot be reliably estimated, are excluded from the estimated annual effective tax rate. In these cases, the actual tax expense or benefit is reported in the same period as the related item. Certain tax effects are also not reflected in the estimated annual effective tax rate, primarily certain changes in the realizability of deferred tax assets and uncertain tax positions. The following table is a reconciliation of the difference in the Company’s income tax expense compared to the federal statutory rate of 21% and 35% for the three months ended March 31, 2018 and 2017 , respectively. Three Months Ended March 31, 2018 2017 NGHC Reciprocal Exchanges Total NGHC Reciprocal Exchanges Total Income (loss) before provision for income taxes $ 86,779 $ (14,557 ) $ 72,222 $ 49,990 $ (8,403 ) $ 41,587 Tax at federal statutory rate $ 18,224 $ (3,057 ) $ 15,167 $ 17,497 $ (2,941 ) $ 14,556 Tax effects resulting from: Exempt foreign income (989 ) — (989 ) (7,196 ) — (7,196 ) Statutory equalization reserves — — — 451 — 451 Other 1,336 688 2,024 2,285 693 2,978 Total income tax reported $ 18,571 $ (2,369 ) $ 16,202 $ 13,037 $ (2,248 ) $ 10,789 Effective tax rate 21.4 % 16.3 % 22.4 % 26.1 % 26.8 % 25.9 % The Company’s consolidated effective tax rate decreased from 25.9% for the three months ended March 31, 2017 to 22.4% for the three months ended March 31, 2018 . The decrease was primarily driven by the change of the federal statutory rate and a reduction in exempt foreign income. All tax liabilities are payable to the Internal Revenue Service (“IRS”) and various state and local taxing agencies. The Company’s subsidiaries are currently open to audit by the IRS for the year ended December 31, 2015, and open to years thereafter for federal tax purposes. For state and local tax purposes, the Company is open to audit for tax years ended December 31, 2014 forward, depending on jurisdiction.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation The Company currently has two equity incentive plans (the “Plans”). The Plans authorize up to an aggregate of 7,435,000 shares of Company stock for awards of options to purchase shares of the Company’s common stock, stock appreciation rights, restricted stock, restricted stock units (“RSU”), unrestricted stock and other performance awards. The aggregate number of shares of common stock for which awards may be issued may not exceed 7,435,000 shares, subject to the authority of the Company’s Board of Directors to adjust this amount in the event of a consolidation, reorganization, stock dividend, recapitalization or similar transaction affecting the Company’s common stock. As of March 31, 2018 , 599,007 shares of Company’s common stock remained available for grants under the Plans. A summary of the Company’s stock option awards is shown below: Shares Subject to Options Outstanding March 31, 2018 Number of Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) Outstanding at beginning of period 3,450,585 $ 9.37 Exercised (86,080 ) 6.51 Outstanding at end of period 3,364,505 $ 9.44 4.7 $ 50,032 Exercisable at end of period 3,320,755 $ 9.33 4.7 $ 49,738 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying stock option awards and the closing price of the Company’s common stock of $24.31 , as reported on the Nasdaq Global Select Market on March 31, 2018 . No options were granted, forfeited or expired during the three months ended March 31, 2018 . The total intrinsic value of the options exercised for the three months ended March 31, 2018 and 2017 was $1,502 and $396 , respectively. The total fair value of stock options vested for the three months ended March 31, 2018 and 2017 was $221 and $236 , respectively. A summary of the Company’s RSUs is shown below: RSUs March 31, 2018 Number of RSUs Weighted-Average Grant Date Fair Value Non-vested at beginning of period 845,459 $ 21.83 Granted 380,850 20.15 Vested (174,411 ) 22.26 Forfeited (13,296 ) 19.92 Non-vested at end of period 1,038,602 $ 21.16 The weighted-average grant date fair value of RSUs granted for the three months ended March 31, 2018 and 2017 was $20.15 and $24.62 , respectively. The total fair value of the RSUs vested for the three months ended March 31, 2018 and 2017 was $3,882 and $1,637 , respectively. Compensation expense, included in general and administrative expenses, for all share-based compensation plans was $2,130 and $2,180 for the three months ended March 31, 2018 and 2017 , respectively. As of March 31, 2018 , the Company had approximately $16,708 of unrecognized share-based compensation expense, of which $16,567 was related to RSUs and $141 to stock options. This unrecognized compensation expense is expected to be recognized over a weighted-average period of approximately 1.7 years.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following is a summary of the elements used in calculating basic and diluted earnings per common share: Three Months Ended March 31, 2018 2017 Numerator: Net income attributable to NGHC $ 68,208 $ 36,923 Less: Dividends on preferred stock (7,875 ) (7,875 ) Net income attributable to NGHC common stockholders $ 60,333 $ 29,048 Denominator: Weighted average number of common shares outstanding – basic 106,758,641 106,467,599 Potentially dilutive securities: Employee stock options 1,922,885 2,154,209 RSUs 269,458 544,873 Weighted average number of common shares outstanding – diluted 108,950,984 109,166,681 Basic earnings per share attributable to NGHC common stockholders $ 0.57 $ 0.27 Diluted earnings per share attributable to NGHC common stockholders $ 0.55 $ 0.27 Certain options and RSUs were excluded from the earnings per share calculation because the impact would have been anti-dilutive. These excluded options and RSUs were not material for the three months ended March 31, 2018 and 2017 , respectively.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The significant shareholder of the Company has an ownership interest in AmTrust, Maiden Holdings Ltd. (“Maiden”) and ACP Re. The Company provides and receives services to and from these related entities as follows: Agreements with AmTrust and Affiliated Entities Asset Management Agreement Pursuant to an asset management agreement among the Company and AmTrust, the Company pays AmTrust a fee for managing the Company’s investment portfolio. AmTrust provides investment management services for a quarterly fee of 0.0375% of the average value of assets under management if the average value of the account for the previous calendar quarter is greater than $1 billion . The amounts charged for such expenses were $651 and $1,115 for the three months ended March 31, 2018 and 2017 , respectively. As of March 31, 2018 and December 31, 2017 , there was a payable to AmTrust related to these services in the amount of $1,416 and $1,208 , respectively. The asset management agreement was terminated effective May 1, 2018 . Asset Purchase and Master Services Agreements On September 13, 2017 , the Company entered into an asset purchase and license agreement (the “Agreement”) with AmTrust, pursuant to which the Company acquired ownership of a policy management system and the related intellectual property, as well as a non-exclusive perpetual license to certain software programs used by the system (the “System”), for a purchase price of $200,000 , including license fees which would have been payable for use of the System during the third quarter 2017. The purchase price is payable in three equal installments in the amount of $66,667 , with the first payment made upon the execution of the Agreement, the second payment made upon the 6-month anniversary of the Agreement, and the third payment payable upon the later of the completion of the full separation and transfer of the System to the Company’s operating environment and the 18-month anniversary of the Agreement. In addition, the Company will be required to pay AmTrust costs for the implementation of the System within the Company's technology environment (up to $5,000 ). The Agreement also terminated the existing master services agreement between the Company and AmTrust. AmTrust will continue to provide printing and mailing services, and management of the premium receipts from its lockbox facilities during a transition period pursuant to the Agreement under the same terms as those provided under the master services agreement. The Company recorded expenses related to this agreement of $3,756 and $15,056 for the three months ended March 31, 2018 and 2017 , respectively. NGHC Quota Share Agreement The Company participated in a quota share reinsurance treaty with ACP Re, Maiden and AmTrust, whereby the Company ceded 50% of the total net earned premiums, net of a ceding commission, and net incurred losses and LAE on business with effective dates after March 1, 2010 (“NGHC Quota Share”). In August 2013, the Company terminated the NGHC Quota Share agreement on a run-off basis. The net reinsurance recoverable is $11,399 and $15,688 at March 31, 2018 and December 31, 2017 , respectively. The net recovery under the agreement was $97 and $2,436 during the three months ended March 31, 2018 and 2017 , respectively. The agreement also stipulates that if the Company would be denied full statutory credit for reinsurance ceded pursuant to the credit for reinsurance laws or regulations in any applicable jurisdiction, the reinsurers will secure an amount equal to that obligation through a letter of credit; assets held in trust for the benefit of the Company or cash. ACP Re and Maiden held assets in trust in the amount of $6,492 and $11,438 , respectively, as of March 31, 2018 and $6,530 and $13,834 , respectively, as of December 31, 2017 . Equity Method Investments The Company has ownership interests in LSC Entities, limited liability companies and limited partnerships with related parties. See Note 4 , “ Investments - Equity Method Investments - Related Parties” for additional information. Agreements with ACP Re Credit Agreement In 2014, the Company entered into a credit agreement (the “ACP Re Credit Agreement”) by and among AmTrust, as administrative agent, ACP Re, as borrower, ACP Re Holdings, LLC, parent company of ACP Re, as guarantor, and AmTrust and the Company, as lenders, pursuant to which the lenders made a $250,000 loan ( $125,000 made by each Lender) to the borrowers on the terms and conditions contained within the ACP Re Credit Agreement. In 2016, the parties entered into a restatement agreement (the “Restatement Agreement”) to the ACP Re Credit Agreement. Under the restated terms, the borrower became ACP Re Holdings, LLC, a Delaware limited liability company owned by a related-party trust, the Michael Karfunkel Family 2005 Trust (the “Trust”). The Trust will cause ACP Re Holdings, LLC to maintain assets having a value greater than 115% of the value of the then outstanding loan balance, and if there is a shortfall, the Trust will make a contribution to ACP Re Holdings, LLC of assets having a market value of at least the shortfall (the “Maintenance Covenant”). The amounts borrowed are secured by equity interests, cash and cash equivalents, other investments held by ACP Re Holdings, LLC and proceeds of the foregoing in an amount equal to the requirements of the Maintenance Covenant. The maturity date of the loan changed to September 20, 2036. The interest rate on the outstanding principal balance of $250,000 changed to a fixed annual rate of 3.7% , provided that up to 1.2% thereof may be paid in kind. Commencing on September 20, 2026, and for each year thereafter, two percent of the then outstanding principal balance of the loan (inclusive of any amounts previously paid in kind) is due and payable. A change of control of greater than 50% and an uncured breach of the Maintenance Covenant are included as events of default. As of March 31, 2018 and December 31, 2017 there was a receivable related to the ACP Re Credit Agreement of $126,930 and $126,173 , respectively. The Company recorded interest income of $1,174 and $1,160 for the three months ended March 31, 2018 and 2017 , respectively, under the ACP Re Credit Agreement. Management evaluates the loan for impairment on a quarterly basis, including the adequacy of the Company’s reserve position based on collateral levels maintained. Management determined no reserve was needed for the carrying value of the loan at March 31, 2018 and December 31, 2017 . Other Related Party Transactions Lease Agreements The Company leases office space at 59 Maiden Lane in New York, New York from 59 Maiden Lane Associates LLC, an entity that is wholly-owned by the Karfunkel family. The lease term is through 2022. The Company paid $207 and $187 in rent for the three months ended March 31, 2018 and 2017 , respectively. The Company leases office space at 30 North LaSalle Street, Chicago, Illinois from 30 North LaSalle Street Partners LLC, an entity that is wholly-owned by the Karfunkel family. The lease term is through 2020. The Company paid $75 and $73 in rent for the three months ended March 31, 2018 and 2017 , respectively.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information The Company currently operates two business segments, “Property and Casualty” and “Accident and Health.” The “Corporate and Other” column represents the activities of the holding company, as well as income from the Company’s investment portfolio. The Company evaluates segment performance based on segment profit separately from the results of the Company’s investment portfolio. Other operating expenses allocated to the segments are called “General and administrative expenses” which are allocated on an actual basis except salaries and benefits where management’s judgment is applied. In determining total assets by segment, the Company identifies those assets that are attributable to a particular segment such as premiums, deferred acquisition costs, reinsurance recoverable, prepaid reinsurance premiums, intangible assets and goodwill, while the remaining assets are allocated to Corporate and Other. The Property and Casualty segment, which includes the Reciprocal Exchanges and the management companies, reports the management fees earned by the Company from the Reciprocal Exchanges for underwriting, investment management and other services as service and fee income. The effects of these transactions between the Company and the Reciprocal Exchanges are eliminated in consolidation to derive consolidated net income. However, the management fee income is reported in net income attributable to NGHC and included in the basic and diluted earnings per share. The following tables summarize the results of operations of the Company’s operating segments: Three Months Ended March 31, 2018 Property and Casualty Accident and Health Corporate and Other Total Underwriting revenue: Gross premium written $ 1,199,354 $ 233,776 $ — $ 1,433,130 Ceded premiums (316,064 ) (10,423 ) — (326,487 ) Net premium written 883,290 223,353 — 1,106,643 Change in unearned premium (131,628 ) (69,477 ) — (201,105 ) Net earned premium 751,662 153,876 — 905,538 Ceding commission income 44,210 258 — 44,468 Service and fee income 96,935 45,187 — 142,122 Total underwriting revenues 892,807 199,321 — 1,092,128 Underwriting expenses: Loss and loss adjustment expense 542,888 91,278 — 634,166 Acquisition costs and other underwriting expenses 125,102 43,608 — 168,710 General and administrative expenses 180,397 50,608 — 231,005 Total underwriting expenses 848,387 185,494 — 1,033,881 Underwriting income 44,420 13,827 — 58,247 Net investment income — — 25,011 25,011 Net gain on investments — — 118 118 Interest expense — — (11,154 ) (11,154 ) Provision for income taxes — — (16,202 ) (16,202 ) Net (income) loss attributable to non-controlling interest — — 12,188 12,188 Net income attributable to NGHC $ 44,420 $ 13,827 $ 9,961 $ 68,208 Three Months Ended March 31, 2017 Property Accident Corporate Total Underwriting revenue: Gross premium written $ 1,061,428 $ 191,955 $ — $ 1,253,383 Ceded premiums (117,489 ) (10,841 ) — (128,330 ) Net premium written 943,939 181,114 — 1,125,053 Change in unearned premium (154,380 ) (52,188 ) — (206,568 ) Net earned premium 789,559 128,926 — 918,485 Ceding commission income 19,707 287 — 19,994 Service and fee income 93,669 32,273 — 125,942 Total underwriting revenues 902,935 161,486 — 1,064,421 Underwriting expenses: Loss and loss adjustment expense 549,434 69,383 — 618,817 Acquisition costs and other underwriting expenses 143,230 31,490 — 174,720 General and administrative expenses 209,972 45,213 — 255,185 Total underwriting expenses 902,636 146,086 — 1,048,722 Underwriting income 299 15,400 — 15,699 Net investment income — — 29,044 29,044 Net loss on investments — — (1,412 ) (1,412 ) Other expense — — 9,801 9,801 Interest expense — — (11,545 ) (11,545 ) Provision for income taxes — — (10,789 ) (10,789 ) Net (income) loss attributable to non-controlling interest — — 6,125 6,125 Net income attributable to NGHC $ 299 $ 15,400 $ 21,224 $ 36,923 The following tables summarize the total assets of the Company’s operating segments: March 31, 2018 Property and Casualty Accident and Health Corporate and Other Total Premiums and other receivables, net $ 1,277,197 $ 209,712 $ 10,962 $ 1,497,871 Deferred acquisition costs 217,083 16,517 — 233,600 Reinsurance recoverable 1,326,151 8,575 — 1,334,726 Prepaid reinsurance premiums 528,770 — — 528,770 Intangible assets, net and Goodwill 458,712 112,847 — 571,559 Prepaid and other assets 15,555 31,163 88,050 134,768 Corporate and other assets — — 4,367,852 4,367,852 Total assets $ 3,823,468 $ 378,814 $ 4,466,864 $ 8,669,146 December 31, 2017 Property and Casualty Accident and Health Corporate and Other Total Premiums and other receivables, net $ 1,177,350 $ 117,000 $ 29,971 $ 1,324,321 Deferred acquisition costs 198,283 18,106 — 216,389 Reinsurance recoverable 1,284,325 9,840 — 1,294,165 Prepaid reinsurance premiums 517,122 — — 517,122 Intangible assets, net and Goodwill 464,153 114,070 — 578,223 Prepaid and other assets 21,141 35,608 99,081 155,830 Corporate and other assets — — 4,353,693 4,353,693 Total assets $ 3,662,374 $ 294,624 $ 4,482,745 $ 8,439,743 The following tables show an analysis of the Company’s premiums by geographical location: Three Months Ended March 31, 2018 2017 NGHC Reciprocal Total NGHC Reciprocal Total Gross premium written - North America $ 1,232,772 $ 97,689 $ 1,330,461 $ 1,094,983 $ 82,216 $ 1,177,199 Gross premium written - Europe 102,669 — 102,669 76,184 — 76,184 Total $ 1,335,441 $ 97,689 $ 1,433,130 $ 1,171,167 $ 82,216 $ 1,253,383 Net premium written - North America $ 953,396 $ 50,578 $ 1,003,974 $ 1,007,168 $ 41,701 $ 1,048,869 Net premium written - Europe 102,669 — 102,669 76,184 — 76,184 Total $ 1,056,065 $ 50,578 $ 1,106,643 $ 1,083,352 $ 41,701 $ 1,125,053 Net earned premium - North America $ 825,112 $ 46,055 $ 871,167 $ 853,528 $ 39,032 $ 892,560 Net earned premium - Europe 34,371 — 34,371 25,925 — 25,925 Total $ 859,483 $ 46,055 $ 905,538 $ 879,453 $ 39,032 $ 918,485 The following tables show an analysis of the Company’s premium by product type: Three Months Ended March 31, Gross Premium Written 2018 2017 Property and Casualty Personal Auto $ 724,645 $ 646,904 Homeowners 140,253 114,201 RV/Packaged 49,464 44,754 Small Business Auto 86,244 86,376 Lender-placed insurance 84,934 76,270 Other 16,125 10,707 Property and Casualty $ 1,101,665 $ 979,212 Accident and Health 233,776 191,955 NGHC Total $ 1,335,441 $ 1,171,167 Reciprocal Exchanges Personal Auto $ 34,297 $ 28,159 Homeowners 62,521 53,327 Other 871 730 Reciprocal Exchanges Total $ 97,689 $ 82,216 Total $ 1,433,130 $ 1,253,383 Three Months Ended March 31, Net Premium Written 2018 2017 Property and Casualty Personal Auto $ 553,997 $ 596,879 Homeowners 92,596 104,545 RV/Packaged 49,189 44,519 Small Business Auto 64,727 79,208 Lender-placed insurance 63,214 72,832 Other 8,989 4,255 Property and Casualty $ 832,712 $ 902,238 Accident and Health 223,353 181,114 NGHC Total $ 1,056,065 $ 1,083,352 Reciprocal Exchanges Personal Auto $ 13,495 $ 17,106 Homeowners 36,808 24,216 Other 275 379 Reciprocal Exchanges Total $ 50,578 $ 41,701 Total $ 1,106,643 $ 1,125,053 Three Months Ended March 31, Net Earned Premium 2018 2017 Property and Casualty Personal Auto $ 454,216 $ 454,415 Homeowners 82,195 104,129 RV/Packaged 45,689 40,650 Small Business Auto 58,562 63,241 Lender-placed insurance 60,469 83,741 Other 4,476 4,351 Property and Casualty $ 705,607 $ 750,527 Accident and Health 153,876 128,926 NGHC Total $ 859,483 $ 879,453 Reciprocal Exchanges Personal Auto $ 12,997 $ 16,117 Homeowners 32,771 22,538 Other 287 377 Reciprocal Exchanges Total $ 46,055 $ 39,032 Total $ 905,538 $ 918,485

Recent Accounting Pronounceme23

Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted During 2018 In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” to remove inconsistencies and weaknesses in revenue requirements, provide a more robust framework for addressing revenue issues, improve comparability of revenue recognition practices, and provide improved disclosure requirements. While the guidance excludes revenue from insurance contracts, investments and financial instruments from its scope, the guidance is applicable to the Company’s service and fee income not specifically exempted from the guidance. The Company adopted ASU 2014-09 effective January 1, 2018, using the modified retrospective method and recorded a cumulative-effect adjustment to the opening balance sheet, increasing retained earnings by $8,830 . See Note 3 , “ Service and Fee Income ” for additional information. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” to provide users of financial statements with more useful information on the recognition, measurement, presentation, and disclosure of financial instruments. Specifically, under ASU 2016-01, equity investments (other than those accounted for using the equity method of accounting or those subject to consolidation) are to be measured at fair value with changes in fair value recognized in earnings. The Company adopted ASU 2016-01 effective January 1, 2018, and recorded a cumulative-effect adjustment to the opening balance sheet, increasing Accumulated Other Comprehensive Income (“AOCI”) by $36 and decreasing retained earnings by the same amount. To conform to the current-year quarter presentation, equity securities are presented in a single line in the Company’s condensed consolidated balance sheets and statements of cash flows. In October 2016, the FASB issued ASU 2016-16 “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory,” which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The Company adopted ASU 2016-16 effective January 1, 2018. Based on the intra-entity transfers of assets executed by the Company, the adoption of this guidance did not have an effect on the Company’s results of operations, financial position or liquidity. Not Yet Adopted With the exception of those adopted above or discussed below, there have been no recent accounting pronouncements, changes in accounting pronouncements, or quantitative or qualitative progress made towards implementation of outstanding accounting pronouncements during the three months ended March 31, 2018 , as compared to those described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , that are of significance, or potential significance, to the Company. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The new standard establishes a right-of-use (ROU) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for fiscal years beginning after December 15, 2018. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is in the early stages of evaluating the impact this guidance will have on its results of operations, financial position or liquidity and disclosures. The Company expects the adoption will have a significant impact on its consolidated financial statements, primarily to the consolidated balance sheets by recognizing a right-of-use asset and corresponding lease liability and related disclosures, due to the addition of operating leases previously accounted for as off-balance sheet transactions. The Company is currently unable to quantify the impact of adopting this guidance.

Service and Fee Income (Tables)

Service and Fee Income (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table summarizes revenue by type and operating segment within service and fee income: Three Months Ended March 31, 2018 2017 Property Accident (1) Total Property Accident Total Commission revenue $ 21,709 $ 17,524 $ 39,233 $ 29,745 $ 10,669 $ 40,414 Finance and processing fees 32,060 1,255 33,315 23,600 2,484 26,084 Installment fees 21,302 — 21,302 18,502 — 18,502 Group health administrative fees — 19,291 19,291 — 14,561 14,561 Late payment fees 7,558 25 7,583 7,600 31 7,631 Other service and fee income 14,306 7,092 21,398 14,222 4,528 18,750 Total $ 96,935 $ 45,187 $ 142,122 $ 93,669 $ 32,273 $ 125,942 NGHC $ 94,489 $ 45,187 $ 139,676 $ 91,589 $ 32,273 $ 123,862 Reciprocal Exchanges 2,446 — 2,446 2,080 — 2,080 Total $ 96,935 $ 45,187 $ 142,122 $ 93,669 $ 32,273 $ 125,942 (1) The impact to commission revenue for the three months ended March 31, 2018 was an increase of $2,501 as a result of applying ASC 606. Prior period amounts have not been adjusted under the modified retrospective method.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Available-for-Sale Debt Securities	The amortized cost, gross unrealized gains and losses, and fair value on available-for-sale debt securities were as follows: March 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury $ 35,830 $ 860 $ (372 ) $ 36,318 Federal agencies 25,711 — (371 ) 25,340 States and political subdivision bonds 384,342 1,510 (7,595 ) 378,257 Foreign government 87,393 1,714 (28 ) 89,079 Corporate bonds 1,118,188 3,525 (22,890 ) 1,098,823 Residential mortgage-backed securities 1,052,632 566 (27,207 ) 1,025,991 Commercial mortgage-backed securities 229,624 593 (6,741 ) 223,476 Asset-backed securities 5,605 236 (103 ) 5,738 Structured securities 358,518 3,308 (528 ) 361,298 Total $ 3,297,843 $ 12,312 $ (65,835 ) $ 3,244,320 NGHC $ 2,981,076 $ 11,504 $ (59,000 ) $ 2,933,580 Reciprocal Exchanges 316,767 808 (6,835 ) 310,740 Total $ 3,297,843 $ 12,312 $ (65,835 ) $ 3,244,320 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury $ 36,236 $ 987 $ (230 ) $ 36,993 Federal agencies 20,711 5 (27 ) 20,689 States and political subdivision bonds 418,557 4,431 (3,907 ) 419,081 Foreign government 55,575 2,736 (57 ) 58,254 Corporate bonds 1,053,777 14,809 (7,697 ) 1,060,889 Residential mortgage-backed securities 1,020,481 211 (15,953 ) 1,004,739 Commercial mortgage-backed securities 143,519 2,340 (1,816 ) 144,043 Asset-backed securities 421 — (7 ) 414 Structured securities 390,514 4,959 (686 ) 394,787 Total $ 3,139,791 $ 30,478 $ (30,380 ) $ 3,139,889 NGHC $ 2,835,293 $ 27,117 $ (27,455 ) $ 2,834,955 Reciprocal Exchanges 304,498 3,361 (2,925 ) 304,934 Total $ 3,139,791 $ 30,478 $ (30,380 ) $ 3,139,889
Available-for-Sale Debt Securities by Contractual Maturity	The amortized cost and fair value of available-for-sale debt securities held as of March 31, 2018 , by contractual maturity, are shown in the table below. Actual maturities may differ from contractual maturities because some borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. NGHC Reciprocal Exchanges Total March 31, 2018 Amortized Fair Amortized Fair Amortized Fair Due in one year or less $ 32,184 $ 31,994 $ 5,149 $ 5,182 $ 37,333 $ 37,176 Due after one year through five years 574,994 568,786 150,573 146,766 725,567 715,552 Due after five years through ten years 868,737 856,975 66,330 65,344 935,067 922,319 Due after ten years 297,644 299,553 14,371 14,515 312,015 314,068 Mortgage-backed securities 1,207,517 1,176,272 80,344 78,933 1,287,861 1,255,205 Total $ 2,981,076 $ 2,933,580 $ 316,767 $ 310,740 $ 3,297,843 $ 3,244,320
Gross Unrealized Losses	The tables below summarize the gross unrealized losses on debt securities classified as available for sale, by length of time the security has continuously been in an unrealized loss position. Less Than 12 Months 12 Months or More Total March 31, 2018 Fair Unrealized No. of Fair Unrealized No. of Fair Unrealized U.S. Treasury $ 20,464 $ (270 ) 131 $ 11,543 $ (102 ) 134 $ 32,007 $ (372 ) Federal agencies 24,738 (343 ) 15 602 (28 ) 4 25,340 (371 ) States and political subdivision bonds 192,758 (4,198 ) 302 82,744 (3,397 ) 119 275,502 (7,595 ) Foreign government 21,588 (28 ) 2 — — — 21,588 (28 ) Corporate bonds 726,521 (17,230 ) 738 109,865 (5,660 ) 96 836,386 (22,890 ) Residential mortgage-backed securities 890,769 (22,670 ) 99 84,388 (4,537 ) 7 975,157 (27,207 ) Commercial mortgage-backed securities 164,033 (5,987 ) 17 12,360 (754 ) 14 176,393 (6,741 ) Asset-backed securities 318 (47 ) 1 1,585 (56 ) 7 1,903 (103 ) Structured securities 52,459 (399 ) 34 6,022 (129 ) 3 58,481 (528 ) Total $ 2,093,648 $ (51,172 ) 1,339 $ 309,109 $ (14,663 ) 384 $ 2,402,757 $ (65,835 ) NGHC $ 1,857,583 $ (45,042 ) 1,203 $ 292,084 $ (13,958 ) 375 $ 2,149,667 $ (59,000 ) Reciprocal Exchanges 236,065 (6,130 ) 136 17,025 (705 ) 9 253,090 (6,835 ) Total $ 2,093,648 $ (51,172 ) 1,339 $ 309,109 $ (14,663 ) 384 $ 2,402,757 $ (65,835 ) Less Than 12 Months 12 Months or More Total December 31, 2017 Fair Unrealized No. of Fair Unrealized No. of Fair Unrealized U.S. Treasury $ 21,567 $ (131 ) 62 $ 10,555 $ (99 ) 20 $ 32,122 $ (230 ) Federal agencies 10,069 (11 ) 6 615 (16 ) 4 10,684 (27 ) States and political subdivision bonds 145,396 (1,851 ) 215 86,894 (2,056 ) 125 232,290 (3,907 ) Foreign government — — — 2,443 (57 ) 2 2,443 (57 ) Corporate bonds 402,236 (4,564 ) 341 110,207 (3,133 ) 93 512,443 (7,697 ) Residential mortgage-backed securities 886,032 (13,476 ) 72 89,412 (2,477 ) 9 975,444 (15,953 ) Commercial mortgage-backed securities 50,537 (727 ) 14 27,072 (1,089 ) 27 77,609 (1,816 ) Asset-backed securities — — — 414 (7 ) 2 414 (7 ) Structured securities 73,561 (631 ) 18 3,727 (55 ) 4 77,288 (686 ) Total $ 1,589,398 $ (21,391 ) 728 $ 331,339 $ (8,989 ) 286 $ 1,920,737 $ (30,380 ) NGHC $ 1,408,081 $ (19,254 ) 623 $ 300,732 $ (8,201 ) 268 $ 1,708,813 $ (27,455 ) Reciprocal Exchanges 181,317 (2,137 ) 105 30,607 (788 ) 18 211,924 (2,925 ) Total $ 1,589,398 $ (21,391 ) 728 $ 331,339 $ (8,989 ) 286 $ 1,920,737 $ (30,380 )
Equity Securities	The fair values on equity securities were as follows: March 31, 2018 December 31, 2017 Common stock $ 47,993 $ 48,119 Preferred stock 2,164 2,222 Total $ 50,157 $ 50,341 NGHC $ 50,157 $ 50,341 Reciprocal Exchanges — — Total $ 50,157 $ 50,341
Investment Income	The components of net investment income consisted of the following: Three Months Ended March 31, 2018 2017 Cash and short-term investments $ 187 $ 34 Debt securities 24,256 26,818 Equity securities 155 75 Other income, net (related parties - $(295) and $3,814) 1,821 3,818 Investment income 26,419 30,745 Investment expenses (1,408 ) (1,701 ) Net Investment Income $ 25,011 $ 29,044 NGHC $ 22,867 $ 26,160 Reciprocal Exchanges 2,144 2,884 Net Investment Income $ 25,011 $ 29,044
Net Realized Gains (Losses)	The table below indicates realized gains and losses. Three Months Ended March 31, 2018 2017 Gross Gross Net Gains (Losses) Gross Gains Gross Losses Net Gains (Losses) Debt securities, available-for-sale $ 1,169 $ (1,171 ) $ (2 ) $ 2,487 $ (1,745 ) $ 742 Debt securities, trading — — — 6,902 (9,545 ) (2,643 ) Equity securities 725 (1,773 ) (1,048 ) 8,027 (8,187 ) (160 ) Foreign exchange and other investments, net 1,168 — 1,168 649 — 649 Net realized gain (loss) on investments $ 3,062 $ (2,944 ) $ 118 $ 18,065 $ (19,477 ) $ (1,412 ) NGHC $ 2,437 $ (2,188 ) $ 249 $ 18,065 $ (19,477 ) $ (1,412 ) Reciprocal Exchanges 625 (756 ) (131 ) — — — Net realized gain (loss) on investments $ 3,062 $ (2,944 ) $ 118 $ 18,065 $ (19,477 ) $ (1,412 ) Net gains and losses recognized during the reporting period on equity securities and debt securities classified as trading still held at the reporting date were as follows: Three Months Ended March 31, 2018 2017 Equity Equity Securities and Debt Securities Net losses recognized during the period $ (1,048 ) $ (5,662 ) Less: Net losses recognized during the period on securities sold during the period — (1,800 ) Net losses recognized during the reporting period on securities still held at the reporting date $ (1,048 ) $ (3,862 )
Credit Quality of Investments	The tables below summarize the credit quality of the Company’s debt securities and preferred stock securities, as rated by Standard & Poor’s. NGHC Reciprocal Exchanges March 31, 2018 Cost or Amortized Cost Fair Value Percentage Cost or Amortized Cost Fair Value Percentage U.S. Treasury $ 29,333 $ 29,801 1.0 % $ 6,497 $ 6,517 2.1 % AAA 281,886 282,501 9.6 % 13,245 12,846 4.1 % AA, AA+, AA- 1,438,345 1,401,862 47.8 % 126,409 124,086 39.9 % A, A+, A- 557,155 548,341 18.7 % 154,305 151,145 48.6 % BBB, BBB+, BBB- 570,184 568,001 19.3 % 10,278 10,115 3.3 % BB+ and lower 106,292 105,238 3.6 % 6,033 6,031 2.0 % Total $ 2,983,195 $ 2,935,744 100.0 % $ 316,767 $ 310,740 100.0 % NGHC Reciprocal Exchanges December 31, 2017 Cost or Fair Value Percentage Cost or Amortized Cost Fair Value Percentage U.S. Treasury $ 30,244 $ 31,026 1.1 % $ 5,992 $ 5,967 2.0 % AAA 255,132 259,506 9.1 % 29,540 28,961 9.5 % AA, AA+, AA- 1,399,287 1,382,191 48.7 % 133,250 133,316 43.7 % A, A+, A- 531,185 534,298 18.8 % 135,682 136,657 44.8 % BBB, BBB+, BBB- 574,456 581,406 20.5 % — — — % BB+ and lower 47,542 48,759 1.8 % 34 33 — % Total $ 2,837,846 $ 2,837,186 100.0 % $ 304,498 $ 304,934 100.0 % The tables below summarize the investment quality of the Company’s corporate bond holdings and industry concentrations. March 31, 2018 AAA AA+, A+,A,A- BBB+, BB+ or Fair % of Corporate Bonds: Financial Institutions 3.6 % 2.1 % 25.4 % 10.4 % 2.0 % $ 477,583 43.5 % Industrials 0.5 % 4.3 % 23.9 % 24.2 % 2.4 % 607,146 55.3 % Utilities/Other — % — % 1.1 % 0.1 % — % 14,094 1.2 % Total 4.1 % 6.4 % 50.4 % 34.7 % 4.4 % $ 1,098,823 100.0 % NGHC 3.7 % 2.3 % 36.6 % 33.8 % 4.4 % $ 888,297 80.8 % Reciprocal Exchanges 0.4 % 4.1 % 13.8 % 0.9 % — % 210,526 19.2 % Total 4.1 % 6.4 % 50.4 % 34.7 % 4.4 % $ 1,098,823 100.0 % December 31, 2017 AAA AA+, A+,A,A- BBB+, BB+ or Fair % of Corporate Bonds: Financial Institutions 2.9 % 7.8 % 31.7 % 11.9 % — % $ 575,746 54.3 % Industrials 0.7 % 3.0 % 16.9 % 21.8 % 0.5 % 454,764 42.9 % Utilities/Other — % — % 1.3 % 1.5 % — % 30,388 2.8 % Total 3.6 % 10.8 % 49.9 % 35.2 % 0.5 % $ 1,060,898 100.0 % NGHC 2.9 % 3.4 % 37.1 % 35.2 % 0.5 % $ 839,615 79.1 % Reciprocal Exchanges 0.7 % 7.4 % 12.8 % — % — % 221,283 20.9 % Total 3.6 % 10.8 % 49.9 % 35.2 % 0.5 % $ 1,060,898 100.0 %
Cash, Cash Equivalents and Restricted Cash	The Company’s cash, cash equivalents, and restricted cash are as follows: March 31, 2018 December 31, 2017 Cash and cash equivalents $ 321,937 $ 292,282 Restricted cash and cash equivalents 56,116 65,202 Cash, cash equivalents and restricted cash $ 378,053 $ 357,484
Restricted Investments	The fair values of the Company’s restricted investments are as follows: March 31, 2018 December 31, 2017 State deposits, at fair value $ 76,083 $ 76,996 Restricted investments to trusts, at fair value 108,786 110,314 Total $ 184,869 $ 187,310
Other Investments	The table below summarizes the composition of other investments: March 31, 2018 December 31, 2017 Equity method investments (related parties - $114,871 and $221,375) $ 149,883 $ 256,321 Note receivable - related party. See Note 13, "Related Party Transactions" 126,930 126,173 Long-term Certificates of Deposit (CDs), at cost 20,339 20,339 Investments, at fair value 11,050 10,791 Investments, at cost or amortized cost 7,668 7,668 Total $ 315,870 $ 421,292

Fair Value of Financial Instr26

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	Assets measured at fair value on a recurring basis are as follows: March 31, 2018 Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Available-for-sale debt securities: U.S. Treasury $ 36,318 $ — $ — $ 36,318 Federal agencies 25,340 — — 25,340 States and political subdivision bonds — 374,130 4,127 378,257 Foreign government — 89,079 — 89,079 Corporate bonds — 1,074,310 24,513 1,098,823 Residential mortgage-backed securities — 1,025,991 — 1,025,991 Commercial mortgage-backed securities — 223,476 — 223,476 Asset-backed securities — 5,738 — 5,738 Structured securities — 361,298 — 361,298 Total available-for-sale debt securities 61,658 3,154,022 28,640 3,244,320 Equity securities: Common stock 44,127 — 3,866 47,993 Preferred stock — 1,882 282 2,164 Total equity securities 44,127 1,882 4,148 50,157 Short-term investments 39,969 — — 39,969 Other investments — — 11,050 11,050 Total $ 145,754 $ 3,155,904 $ 43,838 $ 3,345,496 NGHC $ 117,412 $ 2,851,681 $ 43,838 $ 3,012,931 Reciprocal Exchanges 28,342 304,223 — 332,565 Total $ 145,754 $ 3,155,904 $ 43,838 $ 3,345,496 December 31, 2017 Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Available-for-sale debt securities: U.S. Treasury $ 36,993 $ — $ — $ 36,993 Federal agencies 20,689 — — 20,689 States and political subdivision bonds — 415,000 4,081 419,081 Foreign government — 58,254 — 58,254 Corporate bonds — 1,036,344 24,545 1,060,889 Residential mortgage-backed securities — 1,004,739 — 1,004,739 Commercial mortgage-backed securities — 144,043 — 144,043 Asset-backed securities — 414 — 414 Structured securities — 394,787 — 394,787 Total available-for-sale debt securities 57,682 3,053,581 28,626 3,139,889 Equity securities: Common stock 43,067 — 5,052 48,119 Preferred stock — 1,952 270 2,222 Total equity securities 43,067 1,952 5,322 50,341 Short-term investments 38,266 — — 38,266 Other investments — 9 10,782 10,791 Total $ 139,015 $ 3,055,542 $ 44,730 $ 3,239,287 NGHC $ 110,769 $ 2,756,575 $ 44,730 $ 2,912,074 Reciprocal Exchanges 28,246 298,967 — 327,213 Total $ 139,015 $ 3,055,542 $ 44,730 $ 3,239,287
Fair Value, Assets and Liabilities Measured On Recurring Basis Unobservable Input Reconciliation	The following tables provide a reconciliation of recurring fair value measurements of the Company’s Level 3 financial assets: Total gains (losses) included in: Balance as of January 1, 2018 Net Other Purchases Sales Net transfers Balance as of March 31, 2018 Net gains (losses) included in net income on instruments held at end of period States and political subdivision bonds $ 4,081 $ — $ 46 $ — $ — $ — $ 4,127 $ — Corporate bonds 24,545 — (32 ) — — — 24,513 — Common stock 5,052 (1,186 ) — — — — 3,866 (1,186 ) Preferred stock 270 12 — — — — 282 12 Other investments (1) 10,782 794 — — (526 ) — 11,050 794 Total $ 44,730 $ (380 ) $ 14 $ — $ (526 ) $ — $ 43,838 $ (380 ) Total gains (losses) included in: Balance as of January 1, 2017 Net Other Purchases Sales Net transfers Balance as of March 31, 2017 Net gains (losses) included in net income on instruments held at end of period States and political subdivision bonds $ 4,732 $ — $ — $ — $ — $ (4,732 ) $ — $ — Foreign government 1,910 — — — — (1,910 ) — — Corporate bonds 36,044 — 530 — (9,620 ) 287 27,241 — Residential mortgage-backed securities 7,423 — — — — (7,422 ) 1 — Commercial mortgage-backed securities 4,849 — — — — (4,849 ) — — Structured securities 9,055 — — — — (7,054 ) 2,001 — Common stock 6,297 — — 4,119 (6,297 ) 1 4,120 — Preferred stock — — — — — 280 280 — Other investments (1) 9,427 184 — 3,986 (755 ) — 12,842 184 Total $ 79,737 $ 184 $ 530 $ 8,105 $ (16,672 ) $ (25,399 ) $ 46,485 $ 184 (1) Other investments gains and losses recognized in net income are reported within net investment income in the condensed consolidated statements of income.
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The following table presents the carrying amount and fair value estimates of debt not carried at fair value: March 31, 2018 December 31, 2017 Carrying amount Fair value Carrying amount Fair value 7.625% Notes $ 96,778 $ 99,226 $ 96,756 $ 101,640 6.75% Notes 345,947 362,828 345,786 366,131 Subordinated Debentures 72,168 72,084 72,168 72,101 Imperial Surplus Notes 5,000 4,984 5,000 4,984 SPCIC Surplus Notes 4,000 3,995 4,000 3,996 Credit Agreement 190,000 194,167 190,000 195,420 Total $ 713,893 $ 737,284 $ 713,710 $ 744,272

Deferred Acquisition Costs (Tab

Deferred Acquisition Costs (Tables)	3 Months Ended
	Mar. 31, 2018
Deferred Acquisition Costs [Abstract]
Deferred Policy Acquisition Costs	The following table reflects the amounts of policy acquisition costs deferred and amortized: Three Months Ended March 31, 2018 2017 Property Accident Total Property Accident Total Balance at beginning of the period $ 198,283 $ 18,106 $ 216,389 $ 207,597 $ 13,325 $ 220,922 Additions 139,132 5,940 145,072 155,535 21,121 176,656 Amortization (120,332 ) (7,529 ) (127,861 ) (135,114 ) (19,680 ) (154,794 ) Change in DAC 18,800 (1,589 ) 17,211 20,421 1,441 21,862 Balance at end of the period $ 217,083 $ 16,517 $ 233,600 $ 228,018 $ 14,766 $ 242,784 NGHC $ 195,448 $ 16,517 $ 211,965 $ 194,740 $ 14,766 $ 209,506 Reciprocal Exchanges 21,635 — 21,635 33,278 — 33,278 Balance at end of the period $ 217,083 $ 16,517 $ 233,600 $ 228,018 $ 14,766 $ 242,784

Unpaid Losses and Loss Adjust28

Unpaid Losses and Loss Adjustment Expense Reserves (Tables)	3 Months Ended
	Mar. 31, 2018
Insurance [Abstract]
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense	The table below shows the rollforward of loss reserves on a gross and net of reinsurance basis, reflecting changes in losses incurred and paid losses: Three Months Ended March 31, 2018 2017 Property Accident NGHC Reciprocal Total Property Accident NGHC Reciprocal Total Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period $ 2,270,551 $ 249,653 $ 2,520,204 $ 143,353 $ 2,663,557 $ 1,936,391 $ 200,400 $ 2,136,791 $ 137,075 $ 2,273,866 Less: Reinsurance recoverables at beginning of the period (1,067,495 ) (9,840 ) (1,077,335 ) (52,408 ) (1,129,743 ) (827,672 ) (10,933 ) (838,605 ) (42,192 ) (880,797 ) Net balance at beginning of the period 1,203,056 239,813 1,442,869 90,945 1,533,814 1,108,719 189,467 1,298,186 94,883 1,393,069 Incurred losses and LAE related to: Current year 513,526 94,661 608,187 45,917 654,104 525,688 77,703 603,391 30,020 633,411 Prior year (15,169 ) (3,383 ) (18,552 ) (1,386 ) (19,938 ) (4,354 ) (8,320 ) (12,674 ) (1,920 ) (14,594 ) Total incurred 498,357 91,278 589,635 44,531 634,166 521,334 69,383 590,717 28,100 618,817 Paid losses and LAE related to: Current year (202,967 ) (20,290 ) (223,257 ) (19,686 ) (242,943 ) (165,950 ) (14,568 ) (180,518 ) (12,886 ) (193,404 ) Prior year (306,126 ) (47,992 ) (354,118 ) (17,455 ) (371,573 ) (347,864 ) (51,432 ) (399,296 ) (15,246 ) (414,542 ) Total paid (509,093 ) (68,282 ) (577,375 ) (37,141 ) (614,516 ) (513,814 ) (66,000 ) (579,814 ) (28,132 ) (607,946 ) Effect of foreign exchange rates — (1,679 ) (1,679 ) — (1,679 ) — 1,043 1,043 — 1,043 Net balance at end of the period 1,192,320 261,130 1,453,450 98,335 1,551,785 1,116,239 193,893 1,310,132 94,851 1,404,983 Plus reinsurance recoverables at end of the period 1,058,106 8,565 1,066,671 60,461 1,127,132 819,538 10,732 830,270 44,234 874,504 Gross balance at end of period $ 2,250,426 $ 269,695 $ 2,520,121 $ 158,796 $ 2,678,917 $ 1,935,777 $ 204,625 $ 2,140,402 $ 139,085 $ 2,279,487

Reinsurance (Tables)

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2018
Insurance [Abstract]
Schedule of Effect of Reinsurance on Unpaid Loss and LAE Reserves and Unearned Premiums	The following is the effect of reinsurance on unpaid loss and LAE reserves and unearned premiums: March 31, 2018 December 31, 2017 Assumed Ceded Assumed Ceded Unpaid Loss and LAE reserves $ 106,476 $ 1,127,132 $ 134,246 $ 1,129,743 Unearned premiums 35,385 528,770 45,182 517,122
Schedule of Effect of Reinsurance on Premiums	The following is a summary of the effect of reinsurance on premiums and losses: Three Months Ended March 31, 2018 2017 Written Earned Written Earned Premium: Direct $ 1,413,877 $ 1,191,327 $ 1,195,221 $ 935,775 Assumed 19,253 29,051 58,162 98,038 Total Gross Premium 1,433,130 1,220,378 1,253,383 1,033,813 Ceded (326,487 ) (314,840 ) (128,330 ) (115,328 ) Net Premium $ 1,106,643 $ 905,538 $ 1,125,053 $ 918,485
Schedule of Effect of Reinsurance on Losses	Three Months Ended March 31, 2018 2017 Assumed Ceded Assumed Ceded Loss and LAE $ (1,321 ) $ 197,317 $ 29,946 $ 91,552

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Maturities of Long-term Debt	Maturities of the Company’s debt for the years subsequent to March 31, 2018 are as follows: 2018 (remaining nine months) 2019 2020 2021 2022 2023 Thereafter Total 7.625% Notes $ — $ — $ — $ — $ — $ — $ 100,000 $ 100,000 6.75% Notes — — — — — — 350,000 350,000 Subordinated Debentures — — — — — — 72,168 72,168 Imperial Surplus Notes — — — — — — 5,000 5,000 SPCIC Surplus Notes — — — — — — 4,000 4,000 Credit Agreement — — 190,000 — — — — 190,000 Total principal amount of debt $ — $ — $ 190,000 $ — $ — $ — $ 531,168 $ 721,168 Less: Unamortized debt issuance costs and unamortized discount (7,275 ) Carrying amount of debt $ 713,893

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The following table is a reconciliation of the difference in the Company’s income tax expense compared to the federal statutory rate of 21% and 35% for the three months ended March 31, 2018 and 2017 , respectively. Three Months Ended March 31, 2018 2017 NGHC Reciprocal Exchanges Total NGHC Reciprocal Exchanges Total Income (loss) before provision for income taxes $ 86,779 $ (14,557 ) $ 72,222 $ 49,990 $ (8,403 ) $ 41,587 Tax at federal statutory rate $ 18,224 $ (3,057 ) $ 15,167 $ 17,497 $ (2,941 ) $ 14,556 Tax effects resulting from: Exempt foreign income (989 ) — (989 ) (7,196 ) — (7,196 ) Statutory equalization reserves — — — 451 — 451 Other 1,336 688 2,024 2,285 693 2,978 Total income tax reported $ 18,571 $ (2,369 ) $ 16,202 $ 13,037 $ (2,248 ) $ 10,789 Effective tax rate 21.4 % 16.3 % 22.4 % 26.1 % 26.8 % 25.9 %

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation, Stock Options, Activity	A summary of the Company’s stock option awards is shown below: Shares Subject to Options Outstanding March 31, 2018 Number of Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) Outstanding at beginning of period 3,450,585 $ 9.37 Exercised (86,080 ) 6.51 Outstanding at end of period 3,364,505 $ 9.44 4.7 $ 50,032 Exercisable at end of period 3,320,755 $ 9.33 4.7 $ 49,738 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying stock option awards and the closing price of the Company’s common stock of $24.31 , as reported on the Nasdaq Global Select Market on March 31, 2018 .
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	A summary of the Company’s RSUs is shown below: RSUs March 31, 2018 Number of RSUs Weighted-Average Grant Date Fair Value Non-vested at beginning of period 845,459 $ 21.83 Granted 380,850 20.15 Vested (174,411 ) 22.26 Forfeited (13,296 ) 19.92 Non-vested at end of period 1,038,602 $ 21.16

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following is a summary of the elements used in calculating basic and diluted earnings per common share: Three Months Ended March 31, 2018 2017 Numerator: Net income attributable to NGHC $ 68,208 $ 36,923 Less: Dividends on preferred stock (7,875 ) (7,875 ) Net income attributable to NGHC common stockholders $ 60,333 $ 29,048 Denominator: Weighted average number of common shares outstanding – basic 106,758,641 106,467,599 Potentially dilutive securities: Employee stock options 1,922,885 2,154,209 RSUs 269,458 544,873 Weighted average number of common shares outstanding – diluted 108,950,984 109,166,681 Basic earnings per share attributable to NGHC common stockholders $ 0.57 $ 0.27 Diluted earnings per share attributable to NGHC common stockholders $ 0.55 $ 0.27

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables summarize the results of operations of the Company’s operating segments: Three Months Ended March 31, 2018 Property and Casualty Accident and Health Corporate and Other Total Underwriting revenue: Gross premium written $ 1,199,354 $ 233,776 $ — $ 1,433,130 Ceded premiums (316,064 ) (10,423 ) — (326,487 ) Net premium written 883,290 223,353 — 1,106,643 Change in unearned premium (131,628 ) (69,477 ) — (201,105 ) Net earned premium 751,662 153,876 — 905,538 Ceding commission income 44,210 258 — 44,468 Service and fee income 96,935 45,187 — 142,122 Total underwriting revenues 892,807 199,321 — 1,092,128 Underwriting expenses: Loss and loss adjustment expense 542,888 91,278 — 634,166 Acquisition costs and other underwriting expenses 125,102 43,608 — 168,710 General and administrative expenses 180,397 50,608 — 231,005 Total underwriting expenses 848,387 185,494 — 1,033,881 Underwriting income 44,420 13,827 — 58,247 Net investment income — — 25,011 25,011 Net gain on investments — — 118 118 Interest expense — — (11,154 ) (11,154 ) Provision for income taxes — — (16,202 ) (16,202 ) Net (income) loss attributable to non-controlling interest — — 12,188 12,188 Net income attributable to NGHC $ 44,420 $ 13,827 $ 9,961 $ 68,208 Three Months Ended March 31, 2017 Property Accident Corporate Total Underwriting revenue: Gross premium written $ 1,061,428 $ 191,955 $ — $ 1,253,383 Ceded premiums (117,489 ) (10,841 ) — (128,330 ) Net premium written 943,939 181,114 — 1,125,053 Change in unearned premium (154,380 ) (52,188 ) — (206,568 ) Net earned premium 789,559 128,926 — 918,485 Ceding commission income 19,707 287 — 19,994 Service and fee income 93,669 32,273 — 125,942 Total underwriting revenues 902,935 161,486 — 1,064,421 Underwriting expenses: Loss and loss adjustment expense 549,434 69,383 — 618,817 Acquisition costs and other underwriting expenses 143,230 31,490 — 174,720 General and administrative expenses 209,972 45,213 — 255,185 Total underwriting expenses 902,636 146,086 — 1,048,722 Underwriting income 299 15,400 — 15,699 Net investment income — — 29,044 29,044 Net loss on investments — — (1,412 ) (1,412 ) Other expense — — 9,801 9,801 Interest expense — — (11,545 ) (11,545 ) Provision for income taxes — — (10,789 ) (10,789 ) Net (income) loss attributable to non-controlling interest — — 6,125 6,125 Net income attributable to NGHC $ 299 $ 15,400 $ 21,224 $ 36,923 The following tables summarize the total assets of the Company’s operating segments: March 31, 2018 Property and Casualty Accident and Health Corporate and Other Total Premiums and other receivables, net $ 1,277,197 $ 209,712 $ 10,962 $ 1,497,871 Deferred acquisition costs 217,083 16,517 — 233,600 Reinsurance recoverable 1,326,151 8,575 — 1,334,726 Prepaid reinsurance premiums 528,770 — — 528,770 Intangible assets, net and Goodwill 458,712 112,847 — 571,559 Prepaid and other assets 15,555 31,163 88,050 134,768 Corporate and other assets — — 4,367,852 4,367,852 Total assets $ 3,823,468 $ 378,814 $ 4,466,864 $ 8,669,146 December 31, 2017 Property and Casualty Accident and Health Corporate and Other Total Premiums and other receivables, net $ 1,177,350 $ 117,000 $ 29,971 $ 1,324,321 Deferred acquisition costs 198,283 18,106 — 216,389 Reinsurance recoverable 1,284,325 9,840 — 1,294,165 Prepaid reinsurance premiums 517,122 — — 517,122 Intangible assets, net and Goodwill 464,153 114,070 — 578,223 Prepaid and other assets 21,141 35,608 99,081 155,830 Corporate and other assets — — 4,353,693 4,353,693 Total assets $ 3,662,374 $ 294,624 $ 4,482,745 $ 8,439,743
Revenue from External Customers by Geographic Areas	The following tables show an analysis of the Company’s premiums by geographical location: Three Months Ended March 31, 2018 2017 NGHC Reciprocal Total NGHC Reciprocal Total Gross premium written - North America $ 1,232,772 $ 97,689 $ 1,330,461 $ 1,094,983 $ 82,216 $ 1,177,199 Gross premium written - Europe 102,669 — 102,669 76,184 — 76,184 Total $ 1,335,441 $ 97,689 $ 1,433,130 $ 1,171,167 $ 82,216 $ 1,253,383 Net premium written - North America $ 953,396 $ 50,578 $ 1,003,974 $ 1,007,168 $ 41,701 $ 1,048,869 Net premium written - Europe 102,669 — 102,669 76,184 — 76,184 Total $ 1,056,065 $ 50,578 $ 1,106,643 $ 1,083,352 $ 41,701 $ 1,125,053 Net earned premium - North America $ 825,112 $ 46,055 $ 871,167 $ 853,528 $ 39,032 $ 892,560 Net earned premium - Europe 34,371 — 34,371 25,925 — 25,925 Total $ 859,483 $ 46,055 $ 905,538 $ 879,453 $ 39,032 $ 918,485
Revenue from External Customers by Product Type	The following tables show an analysis of the Company’s premium by product type: Three Months Ended March 31, Gross Premium Written 2018 2017 Property and Casualty Personal Auto $ 724,645 $ 646,904 Homeowners 140,253 114,201 RV/Packaged 49,464 44,754 Small Business Auto 86,244 86,376 Lender-placed insurance 84,934 76,270 Other 16,125 10,707 Property and Casualty $ 1,101,665 $ 979,212 Accident and Health 233,776 191,955 NGHC Total $ 1,335,441 $ 1,171,167 Reciprocal Exchanges Personal Auto $ 34,297 $ 28,159 Homeowners 62,521 53,327 Other 871 730 Reciprocal Exchanges Total $ 97,689 $ 82,216 Total $ 1,433,130 $ 1,253,383 Three Months Ended March 31, Net Premium Written 2018 2017 Property and Casualty Personal Auto $ 553,997 $ 596,879 Homeowners 92,596 104,545 RV/Packaged 49,189 44,519 Small Business Auto 64,727 79,208 Lender-placed insurance 63,214 72,832 Other 8,989 4,255 Property and Casualty $ 832,712 $ 902,238 Accident and Health 223,353 181,114 NGHC Total $ 1,056,065 $ 1,083,352 Reciprocal Exchanges Personal Auto $ 13,495 $ 17,106 Homeowners 36,808 24,216 Other 275 379 Reciprocal Exchanges Total $ 50,578 $ 41,701 Total $ 1,106,643 $ 1,125,053 Three Months Ended March 31, Net Earned Premium 2018 2017 Property and Casualty Personal Auto $ 454,216 $ 454,415 Homeowners 82,195 104,129 RV/Packaged 45,689 40,650 Small Business Auto 58,562 63,241 Lender-placed insurance 60,469 83,741 Other 4,476 4,351 Property and Casualty $ 705,607 $ 750,527 Accident and Health 153,876 128,926 NGHC Total $ 859,483 $ 879,453 Reciprocal Exchanges Personal Auto $ 12,997 $ 16,117 Homeowners 32,771 22,538 Other 287 377 Reciprocal Exchanges Total $ 46,055 $ 39,032 Total $ 905,538 $ 918,485

Recent Accounting Pronounceme35

Recent Accounting Pronouncements Revenue from Contracts with Customers (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition
Cumulative Effect on Retained Earnings, Net of Tax	$ 8,830

Financial Instruments (Details)

Financial Instruments (Details) - Accounting Standards Update 2016-01 $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Schedule of Available-for-sale Securities
Cumulative Effect on AOCI, Net of Tax	$ 36
Cumulative Effect on Retained Earnings, Net of Tax	$ (36)

Service and Fee Income (Details

Service and Fee Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue
Service and Fee Income	$ 142,122	$ 125,942
NGHC, excluding Reciprocal Exchanges
Disaggregation of Revenue
Service and Fee Income	139,676	123,862
Reciprocal Exchanges
Disaggregation of Revenue
Service and Fee Income	2,446	2,080
Commission revenue
Disaggregation of Revenue
Service and Fee Income	39,233	40,414
Impact to commission revenue in the period of adoption	2,501
Finance and processing fees
Disaggregation of Revenue
Service and Fee Income	33,315	26,084
Installment fees
Disaggregation of Revenue
Service and Fee Income	21,302	18,502
Group health administrative fees
Disaggregation of Revenue
Service and Fee Income	19,291	14,561
Late payment fees
Disaggregation of Revenue
Service and Fee Income	7,583	7,631
Other service and fee income
Disaggregation of Revenue
Service and Fee Income	21,398	18,750
All Products and Services
Disaggregation of Revenue
Service and Fee Income	142,122	125,942
Property and Casualty
Disaggregation of Revenue
Service and Fee Income	96,935	93,669
Property and Casualty | NGHC, excluding Reciprocal Exchanges
Disaggregation of Revenue
Service and Fee Income	94,489	91,589
Property and Casualty | Reciprocal Exchanges
Disaggregation of Revenue
Service and Fee Income	2,446	2,080
Property and Casualty | Commission revenue
Disaggregation of Revenue
Service and Fee Income	21,709	29,745
Property and Casualty | Finance and processing fees
Disaggregation of Revenue
Service and Fee Income	32,060	23,600
Property and Casualty | Installment fees
Disaggregation of Revenue
Service and Fee Income	21,302	18,502
Property and Casualty | Group health administrative fees
Disaggregation of Revenue
Service and Fee Income	0	0
Property and Casualty | Late payment fees
Disaggregation of Revenue
Service and Fee Income	7,558	7,600
Property and Casualty | Other service and fee income
Disaggregation of Revenue
Service and Fee Income	14,306	14,222
Property and Casualty | All Products and Services
Disaggregation of Revenue
Service and Fee Income	96,935	93,669
Accident and Health
Disaggregation of Revenue
Service and Fee Income	45,187	32,273
Accident and Health | NGHC, excluding Reciprocal Exchanges
Disaggregation of Revenue
Service and Fee Income	45,187	32,273
Accident and Health | Reciprocal Exchanges
Disaggregation of Revenue
Service and Fee Income	0	0
Accident and Health | Commission revenue
Disaggregation of Revenue
Service and Fee Income	17,524	10,669
Accident and Health | Finance and processing fees
Disaggregation of Revenue
Service and Fee Income	1,255	2,484
Accident and Health | Installment fees
Disaggregation of Revenue
Service and Fee Income	0	0
Accident and Health | Group health administrative fees
Disaggregation of Revenue
Service and Fee Income	19,291	14,561
Accident and Health | Late payment fees
Disaggregation of Revenue
Service and Fee Income	25	31
Accident and Health | Other service and fee income
Disaggregation of Revenue
Service and Fee Income	7,092	4,528
Accident and Health | All Products and Services
Disaggregation of Revenue
Service and Fee Income	$ 45,187	$ 32,273

Investments - Available-for-Sal

Investments - Available-for-Sale Debt Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Amortized Cost
Total	$ 3,297,843	$ 3,139,791
Gross Unrealized Gains
Total	12,312	30,478
Gross Unrealized Losses
Total	(65,835)	(30,380)
Fair Value
Debt Securities	3,244,320	3,139,889
Fair Value	3,244,320	3,139,889
Other-than-temporary impairments recognized in AOCI	0	0
NGHC, excluding Reciprocal Exchanges
Amortized Cost
Total	2,981,076	2,835,293
Gross Unrealized Gains
Total	11,504	27,117
Gross Unrealized Losses
Total	(59,000)	(27,455)
Fair Value
Fair Value	2,933,580	2,834,955
Reciprocal Exchanges
Amortized Cost
Total	316,767	304,498
Gross Unrealized Gains
Total	808	3,361
Gross Unrealized Losses
Total	(6,835)	(2,925)
Fair Value
Debt Securities	310,740	304,934
Fair Value	310,740	304,934
U.S. Treasury
Amortized Cost
Debt Securities	35,830	36,236
Gross Unrealized Gains
Debt Securities	860	987
Gross Unrealized Losses
Debt Securities	(372)	(230)
Fair Value
Debt Securities	36,318	36,993
U.S. Treasury | NGHC, excluding Reciprocal Exchanges
Amortized Cost
Total	29,333	30,244
Fair Value
Fair Value	29,801	31,026
U.S. Treasury | Reciprocal Exchanges
Amortized Cost
Total	6,497	5,992
Fair Value
Fair Value	6,517	5,967
Federal agencies
Amortized Cost
Debt Securities	25,711	20,711
Gross Unrealized Gains
Debt Securities	0	5
Gross Unrealized Losses
Debt Securities	(371)	(27)
Fair Value
Debt Securities	25,340	20,689
States and political subdivision bonds
Amortized Cost
Debt Securities	384,342	418,557
Gross Unrealized Gains
Debt Securities	1,510	4,431
Gross Unrealized Losses
Debt Securities	(7,595)	(3,907)
Fair Value
Debt Securities	378,257	419,081
Foreign government
Amortized Cost
Debt Securities	87,393	55,575
Gross Unrealized Gains
Debt Securities	1,714	2,736
Gross Unrealized Losses
Debt Securities	(28)	(57)
Fair Value
Debt Securities	89,079	58,254
Corporate bonds
Amortized Cost
Debt Securities	1,118,188	1,053,777
Gross Unrealized Gains
Debt Securities	3,525	14,809
Gross Unrealized Losses
Debt Securities	(22,890)	(7,697)
Fair Value
Debt Securities	1,098,823	1,060,889
Residential mortgage-backed securities
Amortized Cost
Debt Securities	1,052,632	1,020,481
Gross Unrealized Gains
Debt Securities	566	211
Gross Unrealized Losses
Debt Securities	(27,207)	(15,953)
Fair Value
Debt Securities	1,025,991	1,004,739
Commercial mortgage-backed securities
Amortized Cost
Debt Securities	229,624	143,519
Gross Unrealized Gains
Debt Securities	593	2,340
Gross Unrealized Losses
Debt Securities	(6,741)	(1,816)
Fair Value
Debt Securities	223,476	144,043
Asset-backed securities
Amortized Cost
Debt Securities	5,605	421
Gross Unrealized Gains
Debt Securities	236	0
Gross Unrealized Losses
Debt Securities	(103)	(7)
Fair Value
Debt Securities	5,738	414
Structured securities
Amortized Cost
Debt Securities	358,518	390,514
Gross Unrealized Gains
Debt Securities	3,308	4,959
Gross Unrealized Losses
Debt Securities	(528)	(686)
Fair Value
Debt Securities	$ 361,298	$ 394,787

Investments - Available-for-S39

Investments - Available-for-Sale Debt Securities by Contractual Maturity (Details) $ in Thousands	Mar. 31, 2018USD ($)
Amortized Cost
Due in one year or less	$ 37,333
Due after one year through five years	725,567
Due after five years through ten years	935,067
Due after ten years	312,015
Mortgage-backed securities	1,287,861
Debt Securities	3,297,843
Fair Value
Due in one year or less	37,176
Due after one year through five years	715,552
Due after five years through ten years	922,319
Due after ten years	314,068
Mortgage-backed securities	1,255,205
Debt Securities	3,244,320
NGHC, excluding Reciprocal Exchanges
Amortized Cost
Due in one year or less	32,184
Due after one year through five years	574,994
Due after five years through ten years	868,737
Due after ten years	297,644
Mortgage-backed securities	1,207,517
Debt Securities	2,981,076
Fair Value
Due in one year or less	31,994
Due after one year through five years	568,786
Due after five years through ten years	856,975
Due after ten years	299,553
Mortgage-backed securities	1,176,272
Debt Securities	2,933,580
Reciprocal Exchanges
Amortized Cost
Due in one year or less	5,149
Due after one year through five years	150,573
Due after five years through ten years	66,330
Due after ten years	14,371
Mortgage-backed securities	80,344
Debt Securities	316,767
Fair Value
Due in one year or less	5,182
Due after one year through five years	146,766
Due after five years through ten years	65,344
Due after ten years	14,515
Mortgage-backed securities	78,933
Debt Securities	$ 310,740

Investments - Gross Unrealized

Investments - Gross Unrealized Losses (Details) $ in Thousands	Mar. 31, 2018USD ($)investmentsecurity	Dec. 31, 2017USD ($)investmentsecurity
Fair Market Value
Less Than 12 Months	$ 2,093,648	$ 1,589,398
12 Months or More	309,109	331,339
Total	2,402,757	1,920,737
Unrealized Losses
Less Than 12 Months	(51,172)	(21,391)
12 Months or More	(14,663)	(8,989)
Total	$ (65,835)	$ (30,380)
No. of Positions Held
Less Than 12 Months | investment	1,339	728
12 Months or More | investment	384	286
Number of securities with gross unrealized loss | security	1,723	1,014
12 Months or More	$ (14,663)	$ (8,989)
25% of amortized cost or cost	25.00%	25.00%
NGHC, excluding Reciprocal Exchanges
Fair Market Value
Less Than 12 Months	$ 1,857,583	$ 1,408,081
12 Months or More	292,084	300,732
Total	2,149,667	1,708,813
Unrealized Losses
Less Than 12 Months	(45,042)	(19,254)
12 Months or More	(13,958)	(8,201)
Total	$ (59,000)	$ (27,455)
No. of Positions Held
Less Than 12 Months | investment	1,203	623
12 Months or More | investment	375	268
12 Months or More	$ (13,958)	$ (8,201)
Reciprocal Exchanges
Fair Market Value
Less Than 12 Months	236,065	181,317
12 Months or More	17,025	30,607
Total	253,090	211,924
Unrealized Losses
Less Than 12 Months	(6,130)	(2,137)
12 Months or More	(705)	(788)
Total	$ (6,835)	$ (2,925)
No. of Positions Held
Less Than 12 Months | investment	136	105
12 Months or More | investment	9	18
12 Months or More	$ (705)	$ (788)
U.S. Treasury
Fair Market Value
Less Than 12 Months	20,464	21,567
12 Months or More	11,543	10,555
Total	32,007	32,122
Unrealized Losses
Less Than 12 Months	(270)	(131)
12 Months or More	(102)	(99)
Total	$ (372)	$ (230)
No. of Positions Held
Less Than 12 Months | investment	131	62
12 Months or More | investment	134	20
12 Months or More	$ (102)	$ (99)
Federal agencies
Fair Market Value
Less Than 12 Months	24,738	10,069
12 Months or More	602	615
Total	25,340	10,684
Unrealized Losses
Less Than 12 Months	(343)	(11)
12 Months or More	(28)	(16)
Total	$ (371)	$ (27)
No. of Positions Held
Less Than 12 Months | investment	15	6
12 Months or More | investment	4	4
12 Months or More	$ (28)	$ (16)
States and political subdivision bonds
Fair Market Value
Less Than 12 Months	192,758	145,396
12 Months or More	82,744	86,894
Total	275,502	232,290
Unrealized Losses
Less Than 12 Months	(4,198)	(1,851)
12 Months or More	(3,397)	(2,056)
Total	$ (7,595)	$ (3,907)
No. of Positions Held
Less Than 12 Months | investment	302	215
12 Months or More | investment	119	125
12 Months or More	$ (3,397)	$ (2,056)
Foreign government
Fair Market Value
Less Than 12 Months	21,588	0
12 Months or More	0	2,443
Total	21,588	2,443
Unrealized Losses
Less Than 12 Months	(28)	0
12 Months or More	0	(57)
Total	$ (28)	$ (57)
No. of Positions Held
Less Than 12 Months | investment	2	0
12 Months or More | investment	0	2
12 Months or More	$ 0	$ (57)
Corporate bonds
Fair Market Value
Less Than 12 Months	726,521	402,236
12 Months or More	109,865	110,207
Total	836,386	512,443
Unrealized Losses
Less Than 12 Months	(17,230)	(4,564)
12 Months or More	(5,660)	(3,133)
Total	$ (22,890)	$ (7,697)
No. of Positions Held
Less Than 12 Months | investment	738	341
12 Months or More | investment	96	93
12 Months or More	$ (5,660)	$ (3,133)
Residential mortgage-backed securities
Fair Market Value
Less Than 12 Months	890,769	886,032
12 Months or More	84,388	89,412
Total	975,157	975,444
Unrealized Losses
Less Than 12 Months	(22,670)	(13,476)
12 Months or More	(4,537)	(2,477)
Total	$ (27,207)	$ (15,953)
No. of Positions Held
Less Than 12 Months | investment	99	72
12 Months or More | investment	7	9
12 Months or More	$ (4,537)	$ (2,477)
Commercial mortgage-backed securities
Fair Market Value
Less Than 12 Months	164,033	50,537
12 Months or More	12,360	27,072
Total	176,393	77,609
Unrealized Losses
Less Than 12 Months	(5,987)	(727)
12 Months or More	(754)	(1,089)
Total	$ (6,741)	$ (1,816)
No. of Positions Held
Less Than 12 Months | investment	17	14
12 Months or More | investment	14	27
12 Months or More	$ (754)	$ (1,089)
Asset-backed securities
Fair Market Value
Less Than 12 Months	318	0
12 Months or More	1,585	414
Total	1,903	414
Unrealized Losses
Less Than 12 Months	(47)	0
12 Months or More	(56)	(7)
Total	$ (103)	$ (7)
No. of Positions Held
Less Than 12 Months | investment	1	0
12 Months or More | investment	7	2
12 Months or More	$ (56)	$ (7)
Structured securities
Fair Market Value
Less Than 12 Months	52,459	73,561
12 Months or More	6,022	3,727
Total	58,481	77,288
Unrealized Losses
Less Than 12 Months	(399)	(631)
12 Months or More	(129)	(55)
Total	$ (528)	$ (686)
No. of Positions Held
Less Than 12 Months | investment	34	18
12 Months or More | investment	3	4
12 Months or More	$ (129)	$ (55)

Investments - Equity Securities

Investments - Equity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Equity Securities
Equity securities	$ 50,157	$ 50,341
NGHC, excluding Reciprocal Exchanges
Schedule of Equity Securities
Equity securities	50,157	50,341
Reciprocal Exchanges
Schedule of Equity Securities
Equity securities	0	0
Common stock
Schedule of Equity Securities
Equity securities	47,993	48,119
Preferred Stock
Schedule of Equity Securities
Equity securities	$ 2,164	$ 2,222

Investments - Investment Income

Investments - Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net Investment Income
Investment Income, Interest	$ 26,419	$ 30,745
Investment expenses	(1,408)	(1,701)
Net Investment Income	25,011	29,044
NGHC, excluding Reciprocal Exchanges
Net Investment Income
Net Investment Income	22,867	26,160
Reciprocal Exchanges
Net Investment Income
Net Investment Income	2,144	2,884
Cash and short-term investments
Net Investment Income
Investment Income, Interest	187	34
Debt securities
Net Investment Income
Investment Income, Interest	24,256	26,818
Equity securities
Net Investment Income
Investment Income, Interest	155	75
Other income, net (related parties - $(295) and $3,814)
Net Investment Income
Investment income	1,821	3,818
Other income, net (related parties - $(295) and $3,814) | Related Parties
Net Investment Income
Investment income	$ (295)	$ 3,814

Investments - Net Realized Gain

Investments - Net Realized Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Gain (Loss) on Investments
Equity Securities and Debt Securities-trading, Gain (Loss), net	$ (1,048)	$ (3,862)
Other, Gross Realized Gains	1,168	649
Other, Gross Realized Losses	0	0
Other Investments, Gains (Losses), Net	1,168	649
Net Gain (Loss) on Investments	118	(1,412)
Net losses recognized during the period	(1,048)	(5,662)
Less: Net losses recognized during the period on securities sold during the period	0	(1,800)
Debt securities
Gain (Loss) on Investments
Available-for-sale Securities, Gross Realized Gains	1,169	2,487
Available-for-sale Securities, Gross Realized Losses	(1,171)	(1,745)
Available-for-sale Securities, Gain (Loss), net	(2)	742
Equity Securities and Debt Securities-trading, Gross Gains	0	6,902
Equity Securities and Debt Securities-trading, Gross Losses	0	(9,545)
Equity Securities and Debt Securities-trading, Gain (Loss), net	0	(2,643)
Equity securities
Gain (Loss) on Investments
Equity Securities and Debt Securities-trading, Gross Gains	725	8,027
Equity Securities and Debt Securities-trading, Gross Losses	(1,773)	(8,187)
Equity Securities and Debt Securities-trading, Gain (Loss), net	(1,048)	(160)
Fixed maturities and equity securities
Gain (Loss) on Investments
Gross Gains on Investments	3,062	18,065
Gross Losses on Investments	(2,944)	(19,477)
Net Gain (Loss) on Investments	118	(1,412)
Fixed maturities and equity securities | NGHC, excluding Reciprocal Exchanges
Gain (Loss) on Investments
Gross Gains on Investments	2,437	18,065
Gross Losses on Investments	(2,188)	(19,477)
Net Gain (Loss) on Investments	249	(1,412)
Fixed maturities and equity securities | Reciprocal Exchanges
Gain (Loss) on Investments
Gross Gains on Investments	625	0
Gross Losses on Investments	(756)	0
Net Gain (Loss) on Investments	$ (131)	$ 0

Investments - Credit Quality of

Investments - Credit Quality of Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 3,297,843	$ 3,139,791
Fair Value	3,244,320	3,139,889
NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	2,981,076	2,835,293
Fair Value	2,933,580	2,834,955
Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	316,767	304,498
Fair Value	310,740	304,934
Fixed Maturity And Preferred Securities | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	2,983,195	2,837,846
Fair Value	$ 2,935,744	$ 2,837,186
Percentage	100.00%	100.00%
Fixed Maturity And Preferred Securities | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 316,767	$ 304,498
Fair Value	$ 310,740	$ 304,934
Percentage	100.00%	100.00%
U.S. Treasury | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 29,333	$ 30,244
Fair Value	$ 29,801	$ 31,026
Percentage	1.00%	1.10%
U.S. Treasury | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 6,497	$ 5,992
Fair Value	$ 6,517	$ 5,967
Percentage	2.10%	2.00%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, AAA Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 281,886	$ 255,132
Fair Value	$ 282,501	$ 259,506
Percentage	9.60%	9.10%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, AAA Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 13,245	$ 29,540
Fair Value	$ 12,846	$ 28,961
Percentage	4.10%	9.50%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, AA, AA Plus, and AA Minus Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 1,438,345	$ 1,399,287
Fair Value	$ 1,401,862	$ 1,382,191
Percentage	47.80%	48.70%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, AA, AA Plus, and AA Minus Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 126,409	$ 133,250
Fair Value	$ 124,086	$ 133,316
Percentage	39.90%	43.70%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, A, A Plus, and A Minus Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 557,155	$ 531,185
Fair Value	$ 548,341	$ 534,298
Percentage	18.70%	18.80%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, A, A Plus, and A Minus Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 154,305	$ 135,682
Fair Value	$ 151,145	$ 136,657
Percentage	48.60%	44.80%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 570,184	$ 574,456
Fair Value	$ 568,001	$ 581,406
Percentage	19.30%	20.50%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 10,278	$ 0
Fair Value	$ 10,115	$ 0
Percentage	3.30%	0.00%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, BB Plus and Lower Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 106,292	$ 47,542
Fair Value	$ 105,238	$ 48,759
Percentage	3.60%	1.80%
Debt Securities and Preferred Securities, Excluding US Treasury Securities | Standard & Poor's, BB Plus and Lower Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Cost or Amortized Cost	$ 6,033	$ 34
Fair Value	$ 6,031	$ 33
Percentage	2.00%	0.00%

Investments - Investment Qualit

Investments - Investment Quality of Corporate Bonds (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities
Fair Value	$ 3,244,320	$ 3,139,889
NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Fair Value	2,933,580	2,834,955
Reciprocal Exchanges
Schedule of Available-for-sale Securities
Fair Value	310,740	304,934
Corporate Debt Securities
Schedule of Available-for-sale Securities
Fair Value	$ 1,098,823	$ 1,060,898
% of Corporate Bonds Portfolio	100.00%	100.00%
Corporate Debt Securities | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Fair Value	$ 888,297	$ 839,615
% of Corporate Bonds Portfolio	80.80%	79.10%
Corporate Debt Securities | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Fair Value	$ 210,526	$ 221,283
% of Corporate Bonds Portfolio	19.20%	20.90%
Corporate Debt Securities | Standard & Poor's, AAA Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	4.10%	3.60%
Corporate Debt Securities | Standard & Poor's, AAA Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	3.70%	2.90%
Corporate Debt Securities | Standard & Poor's, AAA Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.40%	0.70%
Corporate Debt Securities | Standard & Poor's, AA, AA Plus, and AA Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	6.40%	10.80%
Corporate Debt Securities | Standard & Poor's, AA, AA Plus, and AA Minus Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	2.30%	3.40%
Corporate Debt Securities | Standard & Poor's, AA, AA Plus, and AA Minus Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	4.10%	7.40%
Corporate Debt Securities | Standard & Poor's, A, A Plus, and A Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	50.40%	49.90%
Corporate Debt Securities | Standard & Poor's, A, A Plus, and A Minus Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	36.60%	37.10%
Corporate Debt Securities | Standard & Poor's, A, A Plus, and A Minus Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	13.80%	12.80%
Corporate Debt Securities | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	34.70%	35.20%
Corporate Debt Securities | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	33.80%	35.20%
Corporate Debt Securities | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.90%	0.00%
Corporate Debt Securities | Standard & Poor's, BB Plus and Lower Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	4.40%	0.50%
Corporate Debt Securities | Standard & Poor's, BB Plus and Lower Rating | NGHC, excluding Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	4.40%	0.50%
Corporate Debt Securities | Standard & Poor's, BB Plus and Lower Rating | Reciprocal Exchanges
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.00%	0.00%
Corporate Debt Securities | Financial Institutions
Schedule of Available-for-sale Securities
Fair Value	$ 477,583	$ 575,746
% of Corporate Bonds Portfolio	43.50%	54.30%
Corporate Debt Securities | Financial Institutions | Standard & Poor's, AAA Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	3.60%	2.90%
Corporate Debt Securities | Financial Institutions | Standard & Poor's, AA, AA Plus, and AA Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	2.10%	7.80%
Corporate Debt Securities | Financial Institutions | Standard & Poor's, A, A Plus, and A Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	25.40%	31.70%
Corporate Debt Securities | Financial Institutions | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	10.40%	11.90%
Corporate Debt Securities | Financial Institutions | Standard & Poor's, BB Plus and Lower Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	2.00%	0.00%
Corporate Debt Securities | Industrials
Schedule of Available-for-sale Securities
Fair Value	$ 607,146	$ 454,764
% of Corporate Bonds Portfolio	55.30%	42.90%
Corporate Debt Securities | Industrials | Standard & Poor's, AAA Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.50%	0.70%
Corporate Debt Securities | Industrials | Standard & Poor's, AA, AA Plus, and AA Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	4.30%	3.00%
Corporate Debt Securities | Industrials | Standard & Poor's, A, A Plus, and A Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	23.90%	16.90%
Corporate Debt Securities | Industrials | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	24.20%	21.80%
Corporate Debt Securities | Industrials | Standard & Poor's, BB Plus and Lower Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	2.40%	0.50%
Corporate Debt Securities | Utilities And Other
Schedule of Available-for-sale Securities
Fair Value	$ 14,094	$ 30,388
% of Corporate Bonds Portfolio	1.20%	2.80%
Corporate Debt Securities | Utilities And Other | Standard & Poor's, AAA Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.00%	0.00%
Corporate Debt Securities | Utilities And Other | Standard & Poor's, AA, AA Plus, and AA Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.00%	0.00%
Corporate Debt Securities | Utilities And Other | Standard & Poor's, A, A Plus, and A Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	1.10%	1.30%
Corporate Debt Securities | Utilities And Other | Standard & Poor's, BBB, BBB Plus, and BBB Minus Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.10%	1.50%
Corporate Debt Securities | Utilities And Other | Standard & Poor's, BB Plus and Lower Rating
Schedule of Available-for-sale Securities
Investment quality - corporate bond holdings and industry concentrations	0.00%	0.00%

Investments - Cash and Cash Equ

Investments - Cash and Cash Equivalents, Restricted Cash and Restricted Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Cash and cash equivalents	$ 321,937	$ 292,282
Restricted cash and cash equivalents	56,116	65,202
Cash, cash equivalents and restricted cash	378,053	357,484	$ 254,995	$ 285,900
State deposits, at fair value	76,083	76,996
Restricted investments to trusts, at fair value	108,786	110,314
Total	$ 184,869	$ 187,310

Investments - Other Investments

Investments - Other Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Investment
Other investments	$ 315,870	$ 421,292
Related Parties
Investment
Other investments	241,801	347,548
Equity method investments (related parties - $114,871 and $221,375)
Investment
Other investments	149,883	256,321
Equity method investments (related parties - $114,871 and $221,375) | Related Parties
Investment
Other investments	114,871	221,375
Note receivable - related party. See Note 13, Related Party Transactions
Investment
Other investments	126,930	126,173
Long-term Certificates of Deposit (CDs), at cost
Investment
Other investments	20,339	20,339
Investments, at fair value
Investment
Other investments	11,050	10,791
Investments, at cost or amortized cost
Investment
Other investments	$ 7,668	$ 7,668

Investments - Related Parties -

Investments - Related Parties - LSC Entities (Details) $ in Thousands	Dec. 28, 2017USD ($)	Mar. 31, 2018USD ($)contract	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)contract
LSC Entities
Schedule of Equity Method Investments
Life Settlement Contracts, Investment Method, Number of Contracts | contract		5		6
Equity investment in unconsolidated subsidiaries				$ 68,085
LSC Entities | AmTrust Financial Services, Inc.
Schedule of Equity Method Investments
Ownership percentage		50.00%
LSC Entities | VIE, Not primary beneficiary
Schedule of Equity Method Investments
Equity investment in unconsolidated subsidiaries		$ 56,348		160,683
Income (Loss) from Equity Method Investments		700	$ 3,875
Contributions		2,000	10,000
Distributions		$ 107,035	$ 0
LSC Entities | VIE, Not primary beneficiary | Related Parties
Schedule of Equity Method Investments
Ownership percentage		50.00%
LSC Entities investment in LP
Schedule of Equity Method Investments
Number of life settlement contracts sold or contributed to unaffiliated third party	136
Life Settlement Contracts Sale Price To Unaffiliated Third Party	$ 217,831
Life Settlement Contracts, Contingent Consideration				$ 39,724
Ownership percentage				30.00%

Investments - Related Parties49

Investments - Related Parties - 800 Superior, LLC (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Related Parties | 800 Superior, LLC
Schedule of Equity Method Investments
Rent expense	$ 722	$ 703
800 Superior, LLC | AmTrust Financial Services, Inc.
Schedule of Equity Method Investments
Ownership percentage	50.00%
800 Superior, LLC | VIE, Not primary beneficiary | Related Parties
Schedule of Equity Method Investments
Ownership percentage	50.00%
Equity investment in unconsolidated subsidiaries	$ 335		$ 1,405
Income (Loss) from Equity Method Investments	$ (1,070)	$ (117)

Investments - Related Parties50

Investments - Related Parties - East Ninth & Superior (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
East Ninth & Superior, LLC | AmTrust Financial Services, Inc.
Schedule of Equity Method Investments
Ownership percentage	50.00%
East Ninth & Superior, LLC | VIE, Not primary beneficiary | Related Parties
Schedule of Equity Method Investments
Ownership percentage	50.00%
Equity investment in unconsolidated subsidiaries	$ 4,267		$ 4,251
Income (Loss) from Equity Method Investments	$ 16	$ 10
Eight Hundred Superior NMTC investment Fund II | AmTrust Financial Services, Inc.
Schedule of Equity Method Investments
Ownership percentage	24.50%
Eight Hundred Superior NMTC investment Fund II | Related Parties
Schedule of Equity Method Investments
Ownership percentage	24.50%

Investments - Related Parties51

Investments - Related Parties - North Dearborn (Details) - North Dearborn Building Company, L.P. - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
AmTrust Financial Services, Inc.
Schedule of Equity Method Investments
Limited Partnership, Percentage Participation	45.00%
NA Advisors GP LLC
Schedule of Equity Method Investments
Limited Partnership, Percentage Participation	10.00%
Limited Partnership, Percentage of Profit Interest	10.00%
VIE, Not primary beneficiary | Related Parties
Schedule of Equity Method Investments
Ownership percentage	45.00%
Equity investment in unconsolidated subsidiaries	$ 7,573		$ 7,582
Income (Loss) from Equity Method Investments	$ (9)	$ (250)

Investments - Related Parties52

Investments - Related Parties - 4455 LBJ Freeway, LLC (Details) - 4455 LBJ Freeway, LLC - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
AmTrust Financial Services, Inc.
Schedule of Equity Method Investments
Limited Partnership, Percentage Participation	50.00%
Related Parties
Schedule of Equity Method Investments
Equity investment in unconsolidated subsidiaries	$ 742		$ 740
Income (Loss) from Equity Method Investments	2	$ 125
Related Parties | 4455 LBJ Freeway, LLC
Schedule of Equity Method Investments
Rent expense	$ 574	$ 424
VIE, Not primary beneficiary | Related Parties
Schedule of Equity Method Investments
Ownership percentage	50.00%

Investments - Related Parties53

Investments - Related Parties - Illinois Center Building, L.P. (Details) - Illinois Center Building, L.P. - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
ACP Re Group, Inc. [Member]
Schedule of Equity Method Investments
Limited Partnership, Percentage Participation	37.50%
ACP Re
Schedule of Equity Method Investments
Limited Partnership, Percentage Participation	15.00%
NA Advisors GP LLC
Schedule of Equity Method Investments
Limited Partnership, Percentage Participation	10.00%
Limited Partnership, Percentage of Profit Interest	10.00%
VIE, Not primary beneficiary | Related Parties
Schedule of Equity Method Investments
Ownership percentage	37.50%
Equity investment in unconsolidated subsidiaries	$ 45,606		$ 46,715
Income (Loss) from Equity Method Investments	$ (1,109)	$ (1,163)

Fair Value of Financial Instr54

Fair Value of Financial Instruments - Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	$ 3,244,320	$ 3,139,889
Short-term investments	39,969	38,266
Other investments	315,870	421,292
Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	310,740	304,934
Short-term investments	21,825	22,279
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	3,244,320	3,139,889
Equity securities, at fair value	50,157	50,341
Total assets	3,345,496	3,239,287
Recurring | NGHC, excluding Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	3,012,931	2,912,074
Recurring | Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	332,565	327,213
Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	61,658	57,682
Equity securities, at fair value	44,127	43,067
Total assets	145,754	139,015
Level 1 | Recurring | NGHC, excluding Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	117,412	110,769
Level 1 | Recurring | Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	28,342	28,246
Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	3,154,022	3,053,581
Equity securities, at fair value	1,882	1,952
Total assets	3,155,904	3,055,542
Level 2 | Recurring | NGHC, excluding Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	2,851,681	2,756,575
Level 2 | Recurring | Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	304,223	298,967
Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	28,640	28,626
Equity securities, at fair value	4,148	5,322
Total assets	43,838	44,730
Level 3 | Recurring | NGHC, excluding Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	43,838	44,730
Level 3 | Recurring | Reciprocal Exchanges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total assets	0	0
U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	36,318	36,993
U.S. Treasury | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	36,318	36,993
U.S. Treasury | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	36,318	36,993
U.S. Treasury | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
U.S. Treasury | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	25,340	20,689
Federal agencies | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	25,340	20,689
Federal agencies | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	25,340	20,689
Federal agencies | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Federal agencies | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
States and political subdivision bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	378,257	419,081
States and political subdivision bonds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	378,257	419,081
States and political subdivision bonds | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
States and political subdivision bonds | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	374,130	415,000
States and political subdivision bonds | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	4,127	4,081
Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	89,079	58,254
Foreign government | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	89,079	58,254
Foreign government | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Foreign government | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	89,079	58,254
Foreign government | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	1,098,823	1,060,889
Corporate bonds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	1,098,823	1,060,889
Corporate bonds | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Corporate bonds | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	1,074,310	1,036,344
Corporate bonds | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	24,513	24,545
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	1,025,991	1,004,739
Residential mortgage-backed securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	1,025,991	1,004,739
Residential mortgage-backed securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Residential mortgage-backed securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	1,025,991	1,004,739
Residential mortgage-backed securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	223,476	144,043
Commercial mortgage-backed securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	223,476	144,043
Commercial mortgage-backed securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Commercial mortgage-backed securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	223,476	144,043
Commercial mortgage-backed securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	5,738	414
Asset-backed securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	5,738	414
Asset-backed securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Asset-backed securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	5,738	414
Asset-backed securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Structured securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	361,298	394,787
Structured securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	361,298	394,787
Structured securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Structured securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	361,298	394,787
Structured securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Securities	0	0
Common stock | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	47,993	48,119
Common stock | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	44,127	43,067
Common stock | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	0	0
Common stock | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	3,866	5,052
Preferred stock | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	2,164	2,222
Preferred stock | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	0	0
Preferred stock | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	1,882	1,952
Preferred stock | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity securities, at fair value	282	270
Short-term investments | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments	39,969	38,266
Short-term investments | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments	39,969	38,266
Short-term investments | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments	0	0
Short-term investments | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments	0	0
Other investments | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other investments	11,050	10,791
Other investments | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other investments	0	0
Other investments | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other investments	0	9
Other investments | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other investments	$ 11,050	$ 10,782

Fair Value of Financial Instr55

Fair Value of Financial Instruments - Changes in Fair Value of Level 3 Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of	$ 44,730	$ 79,737
Net income	(380)	184
Other comprehensive income	14	530
Purchases	0	8,105
Sales	(526)	(16,672)
Net transfers into (out of) Level 3	0	(25,399)
Balance as of	43,838	46,485
Net gains (losses) included in net income on instruments held at end of period	(380)	184
States and political subdivision bonds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of	4,081	4,732
Net income	0	0
Other comprehensive income	46	0
Purchases	0	0
Sales	0	0
Net transfers into (out of) Level 3	0	(4,732)
Balance as of	4,127	0
Net gains (losses) included in net income on instruments held at end of period	0	0
Foreign government
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of		1,910
Net income		0
Other comprehensive income		0
Purchases		0
Sales		0
Net transfers into (out of) Level 3		(1,910)
Balance as of		0
Net gains (losses) included in net income on instruments held at end of period		0
Corporate bonds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of	24,545	36,044
Net income	0	0
Other comprehensive income	(32)	530
Purchases	0	0
Sales	0	(9,620)
Net transfers into (out of) Level 3	0	287
Balance as of	24,513	27,241
Net gains (losses) included in net income on instruments held at end of period	0	0
Residential mortgage-backed securities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of		7,423
Net income		0
Other comprehensive income		0
Purchases		0
Sales		0
Net transfers into (out of) Level 3		(7,422)
Balance as of		1
Net gains (losses) included in net income on instruments held at end of period		0
Commercial mortgage-backed securities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of		4,849
Net income		0
Other comprehensive income		0
Purchases		0
Sales		0
Net transfers into (out of) Level 3		(4,849)
Balance as of		0
Net gains (losses) included in net income on instruments held at end of period		0
Structured securities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of		9,055
Net income		0
Other comprehensive income		0
Purchases		0
Sales		0
Net transfers into (out of) Level 3		(7,054)
Balance as of		2,001
Net gains (losses) included in net income on instruments held at end of period		0
Common Stock
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of	5,052	6,297
Net income	(1,186)	0
Other comprehensive income	0	0
Purchases	0	4,119
Sales	0	(6,297)
Net transfers into (out of) Level 3	0	1
Balance as of	3,866	4,120
Net gains (losses) included in net income on instruments held at end of period	(1,186)	0
Preferred Stock
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of	270	0
Net income	12	0
Other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Net transfers into (out of) Level 3	0	280
Balance as of	282	280
Net gains (losses) included in net income on instruments held at end of period	12	0
Other investments
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Balance as of	10,782	9,427
Net income	794	184
Other comprehensive income	0	0
Purchases	0	3,986
Sales	(526)	(755)
Net transfers into (out of) Level 3	0	0
Balance as of	11,050	12,842
Net gains (losses) included in net income on instruments held at end of period	$ 794	$ 184

Fair Value of Financial Instr56

Fair Value of Financial Instruments - Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt	$ 713,893	$ 713,710
Fair value estimates of debt	737,284	744,272
Senior Notes | 7.625% Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt	96,778	96,756
Senior Notes | 7.625% Notes | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value estimates of debt	99,226	101,640
Senior Notes | 6.75% Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt	345,947	345,786
Senior Notes | 6.75% Notes | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value estimates of debt	362,828	366,131
Surplus Notes | Subordinated Debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt	72,168	72,168
Surplus Notes | Subordinated Debentures | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value estimates of debt	72,084	72,101
Surplus Notes | Imperial Surplus Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt	5,000	5,000
Surplus Notes | Imperial Surplus Notes | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value estimates of debt	4,984	4,984
Surplus Notes | SPCIC Surplus Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt	4,000	4,000
Surplus Notes | SPCIC Surplus Notes | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value estimates of debt	3,995	3,996
Line of Credit | Credit Agreement
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt	190,000	190,000
Line of Credit | Credit Agreement | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value estimates of debt	$ 194,167	$ 195,420

Fair Value of Financial Instr57

Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of investments priced by service	100.00%		100.00%
Net transfers from Level 1 to Level 2	$ 0	$ 0
Net transfers from Level 2 to Level 1	0	0
Net transfers out of Level 3		(31,917)
Net transfers into Level 3		6,518
Net transfers into (out of) Level 3	$ 0	$ (25,399)
Senior Notes | 7.625% Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate on debt	7.625%
Senior Notes | 6.75% Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate on debt	6.75%

Deferred Acquisition Costs (Det

Deferred Acquisition Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Movement Analysis of Deferred Policy Acquisition Costs
Balance at beginning of the period	$ 216,389	$ 220,922
Additions	145,072	176,656
Amortization	(127,861)	(154,794)
Change in DAC	17,211	21,862
Balance at end of the period	233,600	242,784
NGHC, excluding Reciprocal Exchanges
Movement Analysis of Deferred Policy Acquisition Costs
Balance at end of the period	211,965	209,506
Reciprocal Exchanges
Movement Analysis of Deferred Policy Acquisition Costs
Balance at end of the period	21,635	33,278
Property and Casualty
Movement Analysis of Deferred Policy Acquisition Costs
Balance at beginning of the period	198,283	207,597
Additions	139,132	155,535
Amortization	(120,332)	(135,114)
Change in DAC	18,800	20,421
Balance at end of the period	217,083	228,018
Property and Casualty | NGHC, excluding Reciprocal Exchanges
Movement Analysis of Deferred Policy Acquisition Costs
Balance at end of the period	195,448	194,740
Property and Casualty | Reciprocal Exchanges
Movement Analysis of Deferred Policy Acquisition Costs
Balance at end of the period	21,635	33,278
Accident and Health
Movement Analysis of Deferred Policy Acquisition Costs
Balance at beginning of the period	18,106	13,325
Additions	5,940	21,121
Amortization	(7,529)	(19,680)
Change in DAC	(1,589)	1,441
Balance at end of the period	16,517	14,766
Accident and Health | NGHC, excluding Reciprocal Exchanges
Movement Analysis of Deferred Policy Acquisition Costs
Balance at end of the period	16,517	14,766
Accident and Health | Reciprocal Exchanges
Movement Analysis of Deferred Policy Acquisition Costs
Balance at end of the period	$ 0	$ 0

Unpaid Losses and Loss Adjust59

Unpaid Losses and Loss Adjustment Expense Reserves (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Liability for Claims and Claims Adjustment Expense
Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period	$ 2,663,557	$ 2,273,866
Less: Reinsurance recoverables at beginning of the period	(1,129,743)	(880,797)
Net balance at beginning of the period	1,533,814	1,393,069
Current year	654,104	633,411
Prior year	(19,938)	(14,594)
Total incurred	634,166	618,817
Current year	(242,943)	(193,404)
Prior year	(371,573)	(414,542)
Total paid	(614,516)	(607,946)
Effect of foreign exchange rates	(1,679)	1,043
Net balance at end of the period	1,551,785	1,404,983
Plus reinsurance recoverables at end of the period	1,127,132	874,504
Gross balance at end of period	2,678,917	2,279,487
NGHC, excluding Reciprocal Exchanges
Liability for Claims and Claims Adjustment Expense
Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period	2,520,204	2,136,791
Less: Reinsurance recoverables at beginning of the period	(1,077,335)	(838,605)
Net balance at beginning of the period	1,442,869	1,298,186
Current year	608,187	603,391
Prior year	(18,552)	(12,674)
Total incurred	589,635	590,717
Current year	(223,257)	(180,518)
Prior year	(354,118)	(399,296)
Total paid	(577,375)	(579,814)
Effect of foreign exchange rates	(1,679)	1,043
Net balance at end of the period	1,453,450	1,310,132
Plus reinsurance recoverables at end of the period	1,066,671	830,270
Gross balance at end of period	2,520,121	2,140,402
Reciprocal Exchanges
Liability for Claims and Claims Adjustment Expense
Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period	143,353
Gross balance at end of period	158,796
Property and Casualty
Liability for Claims and Claims Adjustment Expense
Prior year	(16,555)	(6,274)
Property and Casualty | NGHC, excluding Reciprocal Exchanges
Liability for Claims and Claims Adjustment Expense
Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period	2,270,551	1,936,391
Less: Reinsurance recoverables at beginning of the period	(1,067,495)	(827,672)
Net balance at beginning of the period	1,203,056	1,108,719
Current year	513,526	525,688
Prior year	(15,169)	(4,354)
Total incurred	498,357	521,334
Current year	(202,967)	(165,950)
Prior year	(306,126)	(347,864)
Total paid	(509,093)	(513,814)
Effect of foreign exchange rates	0	0
Net balance at end of the period	1,192,320	1,116,239
Plus reinsurance recoverables at end of the period	1,058,106	819,538
Gross balance at end of period	2,250,426	1,935,777
Property and Casualty | Reciprocal Exchanges
Liability for Claims and Claims Adjustment Expense
Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period	143,353	137,075
Less: Reinsurance recoverables at beginning of the period	(52,408)	(42,192)
Net balance at beginning of the period	90,945	94,883
Current year	45,917	30,020
Prior year	(1,386)	(1,920)
Total incurred	44,531	28,100
Current year	(19,686)	(12,886)
Prior year	(17,455)	(15,246)
Total paid	(37,141)	(28,132)
Effect of foreign exchange rates	0	0
Net balance at end of the period	98,335	94,851
Plus reinsurance recoverables at end of the period	60,461	44,234
Gross balance at end of period	158,796	139,085
Accident and Health | NGHC, excluding Reciprocal Exchanges
Liability for Claims and Claims Adjustment Expense
Unpaid losses and LAE, gross of related reinsurance recoverable at beginning of the period	249,653	200,400
Less: Reinsurance recoverables at beginning of the period	(9,840)	(10,933)
Net balance at beginning of the period	239,813	189,467
Current year	94,661	77,703
Prior year	(3,383)	(8,320)
Total incurred	91,278	69,383
Current year	(20,290)	(14,568)
Prior year	(47,992)	(51,432)
Total paid	(68,282)	(66,000)
Effect of foreign exchange rates	(1,679)	1,043
Net balance at end of the period	261,130	193,893
Plus reinsurance recoverables at end of the period	8,565	10,732
Gross balance at end of period	$ 269,695	$ 204,625

Reinsurance Effects of Reinsura

Reinsurance Effects of Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Reinsurance Liabilities [Abstract]
Unpaid Loss and LAE reserves, assumed	$ 106,476		$ 134,246
Reinsurance recoverable on unpaid losses, ceded	1,127,132	$ 874,504	1,129,743	$ 880,797
Unearned premiums, assumed	35,385		45,182
Prepaid reinsurance premiums	528,770		$ 517,122
Premiums:
Direct, Written	1,413,877	1,195,221
Direct, Earned	1,191,327	935,775
Assumed premiums written	19,253	58,162
Assumed, Earned	29,051	98,038
Total Gross Premiums, Written	1,433,130	1,253,383
Premiums Earned, Gross	1,220,378	1,033,813
Ceded premiums	(326,487)	(128,330)
Ceded, Earned	(314,840)	(115,328)
Net premium written	1,106,643	1,125,053
Net earned premium	905,538	918,485
Loss and LAE expense:
Assumed Losses and LAE	(1,321)	29,946
Ceded Loss and LAE	$ 197,317	$ 91,552

Reinsurance Narrative (Details)

Reinsurance Narrative (Details) - USD ($) $ in Thousands	May 01, 2018	Jul. 01, 2017	May 01, 2017
Personal Auto
Reinsurance Retention Policy
Reinsurance - Percentage of Business Ceded		15.00%
Reinsurance percentage of ceding commission		31.20%
Liability of the Reinsurer per Risk		$ 5,000
Liability of the Reinsurer per Event		$ 70,000
Homeowners
Reinsurance Retention Policy
Reinsurance - Percentage of Business Ceded		29.60%
Reinsurance percentage of ceding commission		42.50%
Liability of the Reinsurer per Risk		$ 5,000
Liability of the Reinsurer per Event		70,000
Property Catastrophe Program
Reinsurance Retention Policy
Amount of coverage in excess of retention			$ 575,000
Retention amount			$ 70,000
Casualty Program
Reinsurance Retention Policy
Amount of coverage in excess of retention		45,000
Retention amount		$ 5,000
Minimum | Personal Auto
Reinsurance Retention Policy
Reinsurance percentage of ceding commission		29.60%
Loss Ratio		63.40%
Maximum | Personal Auto
Reinsurance Retention Policy
Reinsurance - Percentage of Business Ceded		20.00%
Reinsurance percentage of ceding commission		32.80%
Loss Ratio		66.60%
Subsequent Event | Homeowners
Reinsurance Retention Policy
Reinsurance - Percentage of Business Ceded	42.00%
Reinsurance percentage of ceding commission	38.00%
Reinsurance - Percentage of Business Ceded, Additional	12.40%
Reciprocal Exchanges | Property Catastrophe Program
Reinsurance Retention Policy
Amount of coverage in excess of retention		$ 375,000
Retention amount		$ 20,000

Debt - 7.625% Subordinated Note

Debt - 7.625% Subordinated Notes due 2055 (Details) - Senior Notes - 7.625% Subordinated Notes - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2015
Debt Instrument
Interest rate on debt	7.625%
Proceeds from Debt, Net of Issuance Costs			$ 96,550
Notes payable			$ 100,000
Interest expense on debt	$ 1,906	$ 1,880
Indenture Excess Leverage Ratio | Minimum
Debt Instrument
Ratio of Indebtedness to Net Capital	0.35
Indenture Excess Leverage Ratio | Maximum
Debt Instrument
Ratio of Indebtedness to Net Capital	1

Debt - 6.75% Notes due 2024 (De

Debt - 6.75% Notes due 2024 (Details) - Senior Notes - 6.75% Notes - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2014
Debt Instrument
Interest rate on debt	6.75%
Proceeds from Debt, Net of Issuance Costs			$ 343,850
Notes payable			$ 350,000
Interest expense on debt	$ 5,906	$ 5,825
Indenture Excess Leverage Ratio | Minimum
Debt Instrument
Ratio of Indebtedness to Net Capital	0.35
Indenture Excess Leverage Ratio | Maximum
Debt Instrument
Ratio of Indebtedness to Net Capital	1

Debt - Subordinated Debentures

Debt - Subordinated Debentures (Details) - Surplus Notes - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Nov. 01, 2016
Subordinated Debentures Tranche $41,238
Debt Instrument
Notes Payable			$ 41,238
Debt Instrument, Description of Variable Rate Basis	LIBOR
Subordinated Debentures Tranche $41,238 | LIBOR
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate	3.40%
Subordinated Debentures Tranche $30,930
Debt Instrument
Notes Payable			$ 30,930
Debt Instrument, Description of Variable Rate Basis	LIBOR
Subordinated Debentures Tranche $30,930 | LIBOR
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate	4.25%
Subordinated Debentures
Debt Instrument
Debt Instrument, Redemption Price, Percentage	100.00%
Interest expense on debt	$ 986	$ 1,003

Debt - Imperial-related Debt (D

Debt - Imperial-related Debt (Details) - Surplus Notes - Imperial Surplus Notes - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jun. 27, 2014
Debt Instrument
Notes payable			$ 5,000
Debt Instrument, Description of Variable Rate Basis	LIBOR
Debt Instrument, Redemption Price, Percentage	100.00%
Interest expense on debt	$ 71	$ 63
LIBOR
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate	4.05%

Debt - SPCIC-related Debt (Deta

Debt - SPCIC-related Debt (Details) - Surplus Notes - SPCIC Surplus Notes - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Oct. 07, 2016
Debt Instrument
Notes Payable			$ 4,000
Debt Instrument, Description of Variable Rate Basis	LIBOR
Debt Instrument, Redemption Price, Percentage	100.00%
Interest expense on debt	$ 58	$ 51
LIBOR
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate	4.15%

Debt - Revolving Credit Agreeme

Debt - Revolving Credit Agreement (Details) - Credit Agreement - JPMorgan Chase, N.A. - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Debt Instrument
Proceeds from Lines of Credit	$ 190,000
Line of Credit Facility, Interest Rate at Period End	4.23%
Line of Credit Facility, Maximum Amount Outstanding During Period	$ 245,000
Letter Of Credit Fronting Fee	0.125%
Line of Credit Facility, Commitment Fee Percentage	0.30%
Interest expense on debt	$ 1,684	$ 439
Minimum
Debt Instrument
Line of Credit Facility, Current Borrowing Capacity	$ 112,500
Line of Credit Facility, Commitment Fee Percentage	0.20%
Maximum
Debt Instrument
Line of Credit Facility, Current Borrowing Capacity	$ 50,000
Line of Credit Facility, Commitment Fee Percentage	0.30%
Federal Funds
Debt Instrument
Debt Instrument, Description of Variable Rate Basis	federal funds
Alternate Base Rate Or LIBOR
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate	0.50%
LIBOR
Debt Instrument
Debt Instrument, Description of Variable Rate Basis	LIBOR
Debt Instrument, Basis Spread on Variable Rate	1.00%

Debt - Debt Maturities (Details

Debt - Debt Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument
2018 (remaining nine months)	$ 0
2,019	0
2,020	190,000
2,021	0
2,022	0
2,023	0
Thereafter	531,168
Total principal amount of debt	721,168
Less: Unamortized debt issuance costs and unamortized discount	(7,275)
Carrying amount of debt	713,893	$ 713,710
Credit Agreement | JPMorgan Chase, N.A.
Debt Instrument
2018 (remaining nine months)	0
2,019	0
2,020	190,000
2,021	0
2,022	0
2,023	0
Thereafter	0
Total principal amount of debt	190,000
Senior Notes | 7.625% Notes
Debt Instrument
2018 (remaining nine months)	0
2,019	0
2,020	0
2,021	0
2,022	0
2,023	0
Thereafter	100,000
Total principal amount of debt	100,000
Carrying amount of debt	96,778	96,756
Senior Notes | 6.75% Notes
Debt Instrument
2018 (remaining nine months)	0
2,019	0
2,020	0
2,021	0
2,022	0
2,023	0
Thereafter	350,000
Total principal amount of debt	350,000
Carrying amount of debt	345,947	345,786
Senior Notes | Subordinated Debentures
Debt Instrument
2018 (remaining nine months)	0
2,019	0
2,020	0
2,021	0
2,022	0
2,023	0
Thereafter	72,168
Total principal amount of debt	72,168
Surplus Notes | Subordinated Debentures
Debt Instrument
Carrying amount of debt	72,168	72,168
Surplus Notes | Imperial Surplus Notes
Debt Instrument
2018 (remaining nine months)	0
2,019	0
2,020	0
2,021	0
2,022	0
2,023	0
Thereafter	5,000
Total principal amount of debt	5,000
Carrying amount of debt	5,000	5,000
Surplus Notes | SPCIC Surplus Notes
Debt Instrument
2018 (remaining nine months)	0
2,019	0
2,020	0
2,021	0
2,022	0
2,023	0
Thereafter	4,000
Total principal amount of debt	4,000
Carrying amount of debt	$ 4,000	$ 4,000

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Entity Information
Income (loss) before provision (benefit) for income taxes and earnings (losses) of equity method investments	$ 72,222	$ 41,587
Tax at Federal statutory rate 35%	15,167	14,556
Effective Income Tax Rate Reconciliation, Amount
Exempt foreign income	(989)	(7,196)
Statutory equalization reserves	0	451
Other	2,024	2,978
Total income tax reported	$ 16,202	$ 10,789
Effective tax rate	22.40%	25.90%
NGHC, excluding Reciprocal Exchanges
Entity Information
Income (loss) before provision (benefit) for income taxes and earnings (losses) of equity method investments	$ 86,779	$ 49,990
Tax at Federal statutory rate 35%	18,224	17,497
Effective Income Tax Rate Reconciliation, Amount
Exempt foreign income	(989)	(7,196)
Statutory equalization reserves	0	451
Other	1,336	2,285
Total income tax reported	$ 18,571	$ 13,037
Effective tax rate	21.40%	26.10%
Reciprocal Exchanges
Entity Information
Income (loss) before provision (benefit) for income taxes and earnings (losses) of equity method investments	$ (14,557)	$ (8,403)
Tax at Federal statutory rate 35%	(3,057)	(2,941)
Effective Income Tax Rate Reconciliation, Amount
Exempt foreign income	0	0
Statutory equalization reserves	0	0
Other	688	693
Total income tax reported	$ (2,369)	$ (2,248)
Effective tax rate	16.30%	26.80%

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Entity Information
Federal tax rate	21.00%	35.00%
Effective tax rate	22.40%	25.90%
NGHC, excluding Reciprocal Exchanges
Entity Information
Effective tax rate	21.40%	26.10%
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit)			$ 25,783
Reciprocal Exchanges
Entity Information
Effective tax rate	16.30%	26.80%
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit)			$ (5,194)

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Activity (Details) - Employee stock options $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding
Outstanding at beginning of period | shares	3,450,585
Exercised | shares	86,080
Outstanding at end of period | shares	3,364,505
Exercisable at end of period | shares	3,320,755
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Outstanding at beginning of period | $ / shares	$ 9.37
Exercised | $ / shares	9.44
Outstanding at end of period | $ / shares	6.51
Exercisable at end of period | $ / shares	$ 9.33
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures
Weighted average remaining contractual term for option awards outstanding	4 years 8 months
Intrinsic value of the underlying stock exceeds the exercise price of options outstanding | $	$ 50,032
Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable	4 years 8 months
Intrinsic value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable | $	$ 49,738

Share-Based Compensation - RSU

Share-Based Compensation - RSU Activity (Details) - RSUs - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
RSUs
Non-vested at beginning of period	845,459
Granted	380,850
Vested	(174,411)
Forfeited	(13,296)
Non-vested at end of period	1,038,602
Weighted Average Grant Date Fair Value (in usd per share)
Non-vested at beginning of period	$ 21.83
Granted	20.15	$ 24.62
Vested	22.26
Forfeited	19.92
Non-vested at end of period	$ 21.16
Fair value of RSU's vested	$ 3,882	$ 1,637

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)plan$ / sharesshares	Mar. 31, 2017USD ($)
Share-based Compensation Arrangement by Share-based Payment Award
Number of equity incentive plans | plan	2
Share Price | $ / shares	$ 24.31
Stock-compensation expense	$ 2,130	$ 2,180
Unrecognized compensation cost	$ 16,708
Future period share-based compensation expense period of recognition (in years)	1 year 8 months
Common stock
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares authorized | shares	7,435,000
Number of shares available | shares	599,007
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award
Granted | shares	0
Intrinsic value of stock options exercised	$ 1,502	396
Fair value of stock options vested	221	236
Unrecognized compensation cost	141
RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Fair value of RSU's vested	3,882	$ 1,637
Unrecognized compensation cost	$ 16,567

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share, Diluted
Net income attributable to NGHC	$ 68,208	$ 36,923
Dividends on preferred stock	(7,875)	(7,875)
Net income attributable to NGHC common stockholders	$ 60,333	$ 29,048
Weighted average number of common shares outstanding – basic	106,758,641	106,467,599
Weighted average number of common shares outstanding – diluted	108,950,984	109,166,681
Basic earnings per share (usd per share)	$ 0.57	$ 0.27
Diluted earnings per share (usd per share)	$ 0.55	$ 0.27
Employee stock options
Earnings Per Share, Diluted
Employee stock options	1,922,885	2,154,209
RSUs
Earnings Per Share, Diluted
RSUs	269,458	544,873

Related Party Transactions - As

Related Party Transactions - Asset Management Agreement (Details) - Related Parties - Asset Management Fee - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Related Party Transaction
Asset management fee percentage, above threshold	0.0375%
Asset management fee, threshold to determine fee	$ 1,000,000
Asset management costs	651	$ 1,115
Payable related to management services	$ 1,416		$ 1,208

Related Party Transactions - Ma

Related Party Transactions - Master Service Agreement (Details) - Related Parties - USD ($) $ in Thousands	Sep. 13, 2017	Mar. 31, 2018	Mar. 31, 2017
Purchase Commitment
Related Party Transaction
Payments for Software	$ 200,000
Payments to Acquire Software	66,667
Purchase Commitment | Maximum
Related Party Transaction
Expenses from transactions with related party	$ 5,000
Master Service Agreement
Related Party Transaction
Expenses from transactions with related party		$ 3,756	$ 15,056

Related Party Transactions - NG

Related Party Transactions - NGHC Quota Share Agreement (Details) - Related Parties - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
ACP Re
Related Party Transaction
Assets held-in-trust	$ 6,492		$ 6,530
Maiden
Related Party Transaction
Assets held-in-trust	11,438		13,834
Reinsurance Recoverable on Unpaid Losses | ACP Re, Maiden and AmTrust
Related Party Transaction
Due from (to) reinsurance treaties	11,399		$ 15,688
Amounts of transaction	$ 97	$ 2,436
Reinsurance | ACP Re, Maiden and AmTrust
Related Party Transaction
Percentage of business ceded	50.00%

Related Party Transactions - Ag

Related Party Transactions - Agreements with ACP Re and Affiliated Entities (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2014
Related Party Transaction
Other investments	$ 315,870			$ 421,292
ACP Re
Related Party Transaction
Financing principal amount, aggregate					$ 125,000
Related Parties
Related Party Transaction
Other investments	241,801			347,548
Related Parties | ACP Re
Related Party Transaction
Financing principal amount, aggregate					250,000
Maintenance Covenant, minimum collateral interest as percent of value of outstanding loan balance			115.00%
Minimum percent of change in control included as events of default			50.00%
Related Parties | Loans
Related Party Transaction
Financing principal amount, aggregate					$ 125,000
Related Parties | Loans | ACP Re
Related Party Transaction
Interest rate on debt			3.70%
Maximum percent of interest that may be paid in kind			1.20%
Percent of outstanding principal balance of loan due and payable annually after tenth anniversary			2.00%
Other investments	126,930			$ 126,173
Interest Income, Related Party	$ 1,174	$ 1,160

Related Party Transactions Rela

Related Party Transactions Related Party Transactions - Other Related Party Transactions (Details) - Related Parties - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Lease Agreement 59 Maiden Lane
Related Party Transaction
Expenses from transactions with related party	$ 207	$ 187
Lease Agreement 30 North LaSalle
Related Party Transaction
Expenses from transactions with related party	$ 75	$ 73

Segment Information - Results o

Segment Information - Results of Operations of the Business Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)segment	Mar. 31, 2017USD ($)
Segment Reporting [Abstract]
Number of business segments | segment	2
Segment Reporting Information
Gross premium written	$ 1,433,130	$ 1,253,383
Ceded premiums	(326,487)	(128,330)
Net premium written	1,106,643	1,125,053
Change in unearned premium	(201,105)	(206,568)
Net earned premium	905,538	918,485
Ceding commission income	44,468	19,994
Service and fee income	142,122	125,942
Total underwriting revenues	1,092,128	1,064,421
Loss and loss adjustment expense	634,166	618,817
Acquisition costs and other underwriting expenses	168,710	174,720
General and administrative expenses	231,005	255,185
Total underwriting expenses	1,033,881	1,048,722
Underwriting income	58,247	15,699
Net investment income	25,011	29,044
Net gain (loss) on investments	118	(1,412)
Other income	0	9,801
Interest expense	(11,154)	(11,545)
Provision for income taxes	(16,202)	(10,789)
Net (income) loss attributable to non-controlling interest	12,188	6,125
Net income attributable to NGHC	68,208	36,923
NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	1,335,441	1,171,167
Net premium written	1,056,065	1,083,352
Net earned premium	859,483	879,453
Net investment income	22,867	26,160
Provision for income taxes	(18,571)	(13,037)
Reciprocal Exchanges
Segment Reporting Information
Gross premium written	97,689	82,216
Net premium written	50,578	41,701
Net earned premium	46,055	39,032
Net investment income	2,144	2,884
Provision for income taxes	2,369	2,248
Property and Casualty
Segment Reporting Information
Gross premium written	1,199,354	1,061,428
Ceded premiums	(316,064)	(117,489)
Net premium written	883,290	943,939
Change in unearned premium	(131,628)	(154,380)
Net earned premium	751,662	789,559
Ceding commission income	44,210	19,707
Service and fee income	96,935	93,669
Total underwriting revenues	892,807	902,935
Loss and loss adjustment expense	542,888	549,434
Acquisition costs and other underwriting expenses	125,102	143,230
General and administrative expenses	180,397	209,972
Total underwriting expenses	848,387	902,636
Underwriting income	44,420	299
Net investment income	0	0
Net gain (loss) on investments	0	0
Other income		0
Interest expense	0	0
Provision for income taxes	0	0
Net (income) loss attributable to non-controlling interest	0	0
Net income attributable to NGHC	44,420	299
Property and Casualty | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	1,101,665	979,212
Net premium written	832,712	902,238
Net earned premium	705,607	750,527
Property and Casualty | Reciprocal Exchanges
Segment Reporting Information
Gross premium written	97,689	82,216
Net premium written	50,578	41,701
Net earned premium	46,055	39,032
Accident and Health
Segment Reporting Information
Gross premium written	233,776	191,955
Ceded premiums	(10,423)	(10,841)
Net premium written	223,353	181,114
Change in unearned premium	(69,477)	(52,188)
Net earned premium	153,876	128,926
Ceding commission income	258	287
Service and fee income	45,187	32,273
Total underwriting revenues	199,321	161,486
Loss and loss adjustment expense	91,278	69,383
Acquisition costs and other underwriting expenses	43,608	31,490
General and administrative expenses	50,608	45,213
Total underwriting expenses	185,494	146,086
Underwriting income	13,827	15,400
Net investment income	0	0
Net gain (loss) on investments	0	0
Other income		0
Interest expense	0	0
Provision for income taxes	0	0
Net (income) loss attributable to non-controlling interest	0	0
Net income attributable to NGHC	13,827	15,400
Accident and Health | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	233,776	191,955
Net premium written	223,353	181,114
Net earned premium	153,876	128,926
Corporate and Other
Segment Reporting Information
Gross premium written	0	0
Ceded premiums	0	0
Net premium written	0	0
Change in unearned premium	0	0
Net earned premium	0	0
Ceding commission income	0	0
Service and fee income	0	0
Total underwriting revenues	0	0
Loss and loss adjustment expense	0	0
Acquisition costs and other underwriting expenses	0	0
General and administrative expenses	0	0
Total underwriting expenses	0	0
Underwriting income	0	0
Net investment income	25,011	29,044
Net gain (loss) on investments	118	(1,412)
Other income		9,801
Interest expense	(11,154)	(11,545)
Provision for income taxes	(16,202)	(10,789)
Net (income) loss attributable to non-controlling interest	12,188	6,125
Net income attributable to NGHC	$ 9,961	$ 21,224

Segment Information - Long Live

Segment Information - Long Lived Assets and Total Assets of Business Segments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information
Premiums and other receivables, net	$ 1,497,871	$ 1,324,321
Deferred acquisition costs	233,600	216,389
Reinsurance recoverable	1,334,726	1,294,165
Prepaid reinsurance premiums	528,770	517,122
Intangible assets, net and Goodwill	571,559	578,223
Prepaid and other assets	134,768	155,830
Corporate and other assets	4,367,852	4,353,693
Total assets	8,669,146	8,439,743
Property and Casualty
Segment Reporting Information
Premiums and other receivables, net	1,277,197	1,177,350
Deferred acquisition costs	217,083	198,283
Reinsurance recoverable	1,326,151	1,284,325
Prepaid reinsurance premiums	528,770	517,122
Intangible assets, net and Goodwill	458,712	464,153
Prepaid and other assets	15,555	21,141
Corporate and other assets	0	0
Total assets	3,823,468	3,662,374
Accident and Health
Segment Reporting Information
Premiums and other receivables, net	209,712	117,000
Deferred acquisition costs	16,517	18,106
Reinsurance recoverable	8,575	9,840
Prepaid reinsurance premiums	0	0
Intangible assets, net and Goodwill	112,847	114,070
Prepaid and other assets	31,163	35,608
Corporate and other assets	0	0
Total assets	378,814	294,624
Corporate and Other
Segment Reporting Information
Premiums and other receivables, net	10,962	29,971
Deferred acquisition costs	0	0
Reinsurance recoverable	0	0
Prepaid reinsurance premiums	0	0
Intangible assets, net and Goodwill	0	0
Prepaid and other assets	88,050	99,081
Corporate and other assets	4,367,852	4,353,693
Total assets	$ 4,466,864	$ 4,482,745

Segment Information - Schedule

Segment Information - Schedule of Revenue by Geographical Location (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information
Gross premium written	$ 1,433,130	$ 1,253,383
Net premium written	1,106,643	1,125,053
Net earned premium	905,538	918,485
NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	1,335,441	1,171,167
Net premium written	1,056,065	1,083,352
Net earned premium	859,483	879,453
Reciprocal Exchanges
Segment Reporting Information
Gross premium written	97,689	82,216
Net premium written	50,578	41,701
Net earned premium	46,055	39,032
North America
Segment Reporting Information
Gross premium written	1,330,461	1,177,199
Net premium written	1,003,974	1,048,869
Net earned premium	871,167	892,560
North America | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	1,232,772	1,094,983
Net premium written	953,396	1,007,168
Net earned premium	825,112	853,528
North America | Reciprocal Exchanges
Segment Reporting Information
Gross premium written	97,689	82,216
Net premium written	50,578	41,701
Net earned premium	46,055	39,032
Europe
Segment Reporting Information
Gross premium written	102,669	76,184
Net premium written	102,669	76,184
Net earned premium	34,371	25,925
Europe | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	102,669	76,184
Net premium written	102,669	76,184
Net earned premium	34,371	25,925
Europe | Reciprocal Exchanges
Segment Reporting Information
Gross premium written	0	0
Net premium written	0	0
Net earned premium	$ 0	$ 0

Segment Information - Gross Pre

Segment Information - Gross Premium Written (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information
Gross premium written	$ 1,433,130	$ 1,253,383
NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	1,335,441	1,171,167
Reciprocal Exchanges
Segment Reporting Information
Gross premium written	97,689	82,216
Property and Casualty
Segment Reporting Information
Gross premium written	1,199,354	1,061,428
Property and Casualty | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	1,101,665	979,212
Property and Casualty | Reciprocal Exchanges
Segment Reporting Information
Gross premium written	97,689	82,216
Property and Casualty | Personal Auto | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	724,645	646,904
Property and Casualty | Personal Auto | Reciprocal Exchanges
Segment Reporting Information
Gross premium written	34,297	28,159
Property and Casualty | Homeowners | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	140,253	114,201
Property and Casualty | Homeowners | Reciprocal Exchanges
Segment Reporting Information
Gross premium written	62,521	53,327
Property and Casualty | RV/Packaged | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	49,464	44,754
Property and Casualty | Small Business Auto | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	86,244	86,376
Property and Casualty | Lender-placed insurance | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	84,934	76,270
Property and Casualty | Other | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	16,125	10,707
Property and Casualty | Other | Reciprocal Exchanges
Segment Reporting Information
Gross premium written	871	730
Accident and Health
Segment Reporting Information
Gross premium written	233,776	191,955
Accident and Health | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Gross premium written	$ 233,776	$ 191,955

Segment Information - Net Premi

Segment Information - Net Premium Written (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information
Net premium written	$ 1,106,643	$ 1,125,053
NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	1,056,065	1,083,352
Reciprocal Exchanges
Segment Reporting Information
Net premium written	50,578	41,701
Property and Casualty
Segment Reporting Information
Net premium written	883,290	943,939
Property and Casualty | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	832,712	902,238
Property and Casualty | Reciprocal Exchanges
Segment Reporting Information
Net premium written	50,578	41,701
Property and Casualty | Personal Auto | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	553,997	596,879
Property and Casualty | Personal Auto | Reciprocal Exchanges
Segment Reporting Information
Net premium written	13,495	17,106
Property and Casualty | Homeowners | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	92,596	104,545
Property and Casualty | Homeowners | Reciprocal Exchanges
Segment Reporting Information
Net premium written	36,808	24,216
Property and Casualty | RV/Packaged | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	49,189	44,519
Property and Casualty | Small Business Auto | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	64,727	79,208
Property and Casualty | Lender-placed insurance | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	63,214	72,832
Property and Casualty | Other | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	8,989	4,255
Property and Casualty | Other | Reciprocal Exchanges
Segment Reporting Information
Net premium written	275	379
Accident and Health
Segment Reporting Information
Net premium written	223,353	181,114
Accident and Health | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net premium written	$ 223,353	$ 181,114

Segment Information - Net Earne

Segment Information - Net Earned Premium (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information
Net earned premium	$ 905,538	$ 918,485
NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	859,483	879,453
Reciprocal Exchanges
Segment Reporting Information
Net earned premium	46,055	39,032
Property and Casualty
Segment Reporting Information
Net earned premium	751,662	789,559
Property and Casualty | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	705,607	750,527
Property and Casualty | Reciprocal Exchanges
Segment Reporting Information
Net earned premium	46,055	39,032
Property and Casualty | Personal Auto | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	454,216	454,415
Property and Casualty | Personal Auto | Reciprocal Exchanges
Segment Reporting Information
Net earned premium	12,997	16,117
Property and Casualty | Homeowners | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	82,195	104,129
Property and Casualty | Homeowners | Reciprocal Exchanges
Segment Reporting Information
Net earned premium	32,771	22,538
Property and Casualty | RV/Packaged | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	45,689	40,650
Property and Casualty | Small Business Auto | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	58,562	63,241
Property and Casualty | Lender-placed insurance | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	60,469	83,741
Property and Casualty | Other | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	4,476	4,351
Property and Casualty | Other | Reciprocal Exchanges
Segment Reporting Information
Net earned premium	287	377
Accident and Health
Segment Reporting Information
Net earned premium	153,876	128,926
Accident and Health | NGHC, excluding Reciprocal Exchanges
Segment Reporting Information
Net earned premium	$ 153,876	$ 128,926