Navigators (NAVG) 10-Q 4 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 28, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	NAVG
Entity Registrant Name	NAVIGATORS GROUP INC
Entity Central Index Key	793,547
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		14,559,435

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Investments:
Fixed maturities, available-for-sale, at fair value (amortized cost: 2016: $2,591,050; 2015: $2,400,245)	$ 2,660,417	$ 2,414,210
Equity securities, available-for-sale, at fair value (cost: 2016: $305,906; 2015: $281,943)	342,677	305,271
Other invested assets	2,021
Short-term investments, at fair value (amortized cost: 2016: $134,273; 2015: $217,743)	134,273	217,745
Total investments	3,139,388	2,937,226
Cash	147,515	69,901
Premiums receivable	320,429	276,616
Prepaid reinsurance premiums	222,891	232,588
Reinsurance recoverable on paid losses	73,331	49,506
Reinsurance recoverable on unpaid losses and loss adjustment expenses	787,917	809,518
Deferred policy acquisition costs	116,295	91,983
Accrued investment income	16,840	16,001
Goodwill and other intangible assets	6,568	6,807
Current income tax receivable, net	15,879	22,323
Deferred income tax, net		3,900
Other assets	50,343	67,643
Total assets	4,897,396	4,584,012
Liabilities:
Reserves for losses and loss adjustment expenses	2,268,127	2,202,644
Unearned premiums	897,975	820,676
Reinsurance balances payable	123,702	107,411
Senior notes	263,690	263,580
Deferred income tax, net	8,703
Payable for investments purchased	42,783	1,495
Accounts payable and other liabilities	88,135	92,058
Total liabilities	3,693,115	3,487,864
Stockholders' equity:
Preferred stock, $.10 par value, authorized 1,000,000 shares, none issued
Common stock, $.10 par value, authorized 50,000,000 shares, issued 18,070,815 shares for 2016 and 17,942,269 shares for 2015	1,806	1,793
Additional paid-in capital	368,860	357,829
Treasury stock, at cost (3,511,380 shares for 2016 and 2015)	(155,801)	(155,801)
Retained earnings	927,239	868,723
Accumulated other comprehensive income	62,177	23,604
Total stockholders' equity	1,204,281	1,096,148
Total liabilities and stockholders' equity	$ 4,897,396	$ 4,584,012

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Fixed maturities, available-for-sale, amortized cost	$ 2,591,050	$ 2,400,245
Equity securities, available-for-sale, cost	305,906	281,943
Short-term investments, amortized cost	$ 134,273	$ 217,743
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, authorized shares	1,000,000	1,000,000
Preferred stock, issued shares	0	0
Common stock, par value	$ 0.10	$ 0.10
Common stock, authorized shares	50,000,000	50,000,000
Common stock, issued shares	18,070,815	17,942,269
Treasury stock, shares	3,511,380	3,511,380

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Gross written premiums	$ 374,930	$ 354,062	$ 1,201,372	$ 1,129,993
Revenues:
Net written premiums	277,001	251,939	903,356	799,141
Change in unearned premiums	7,009	2,143	(86,996)	(66,599)
Net earned premiums	284,010	254,082	816,360	732,542
Net investment income	19,875	17,371	59,344	50,219
Total other-than-temporary impairment losses	23	(1,298)	(248)	(1,747)
Portion of loss recognized in other comprehensive income (before tax)	(23)	23	98	49
Net other-than-temporary impairment losses recognized in earnings		(1,275)	(150)	(1,698)
Net realized gains (losses)	1,586	518	5,143	10,453
Other income (expenses)	(183)	(2,518)	6,796	(4,638)
Total revenues	305,288	268,178	887,493	786,878
Expenses:
Net losses and loss adjustment expenses	172,793	146,546	492,955	418,717
Commission expenses	42,611	34,253	120,891	98,638
Other operating expenses	56,137	56,599	176,020	164,297
Interest expense	3,859	3,856	11,575	11,567
Total expenses	275,400	241,254	801,441	693,219
Income before income taxes	29,888	26,924	86,052	93,659
Income tax expense (benefit)	7,875	8,723	24,917	30,345
Net income	$ 22,013	$ 18,201	$ 61,135	$ 63,314
Net income per common share:
Basic	$ 1.51	$ 1.26	$ 4.21	$ 4.40
Diluted	$ 1.46	$ 1.23	$ 4.08	$ 4.29
Average common shares outstanding:
Basic	14,557,376	14,411,927	14,528,917	14,384,291
Diluted	15,070,422	14,811,095	14,998,385	14,767,949

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 22,013	$ 18,201	$ 61,135	$ 63,314
Change in net unrealized gains (losses) on investments:
Unrealized gains (losses) on investments arising during the period, net of deferred tax	(2,414)	1,018	43,362	(18,765)
Reclassification adjustment for net realized (gains) losses included in net income, net of deferred tax	(519)	(544)	1,449	(2,733)
Change in net unrealized gains (losses) on investments	(2,933)	474	44,811	(21,498)
Change in other-than-temporary impairments:
Non credit other-than-temporary impairments arising during the period, net of deferred tax	15	(15)	(64)	(32)
Reclassification adjustment for other-than-temporary impairment credit losses recognized in net income, net of deferred tax		188		316
Change in other-than-temporary impairments	15	173	(64)	284
Change in foreign currency translation gains (losses), net of deferred tax	(335)	1	(6,174)	12
Other comprehensive income (loss)	(3,253)	648	38,573	(21,202)
Comprehensive income (loss)	$ 18,760	$ 18,849	$ 99,708	$ 42,112

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Unrealized gains (losses) on investments arising during the period, deferred tax	$ 1,300	$ (549)	$ (23,349)	$ 9,858
Reclassification adjustment for net realized (gains) losses included in net income, deferred tax	279	293	(780)	1,472
Non credit other-than-temporary impairments arising during the period, deferred tax	(8)	8	34	17
Reclassification adjustment for other-than-temporary impairment credit losses recognized in net income, deferred tax	0	(101)	0	(170)
Change in foreign currency translation gains (losses), deferred tax	$ 175	$ (1)	$ 3,322	$ (6)

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2016 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2015	$ 1,096,148	$ 1,793	$ 357,829	$ (155,801)	$ 868,723	$ 23,604
Beginning balance (in shares) at Dec. 31, 2015	17,942,269	17,942,269		3,511,380
Net income	$ 61,135				61,135
Dividends paid	(2,619)				(2,619)
Changes in comprehensive income:
Change in net unrealized gain (loss) on investments	44,811					44,811
Change in net non-credit other-than-temporary impairment losses	(64)					(64)
Change in foreign currency translation gain (loss)	(6,174)					(6,174)
Other comprehensive income (loss)	38,573					38,573
Shares issued under stock plan	(2,885)	$ 13	(2,898)
Shares issued under stock plan (in shares)		128,546
Share-based compensation	13,929		13,929
Ending balance at Sep. 30, 2016	$ 1,204,281	$ 1,806	$ 368,860	$ (155,801)	$ 927,239	$ 62,177
Ending balance (in shares) at Sep. 30, 2016	18,070,815	18,070,815		3,511,380

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income	$ 61,135	$ 63,314
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation & amortization	4,214	3,892
Deferred income taxes	(7,066)	(185)
Net realized (gains) losses	(5,143)	(10,453)
Net other-than-temporary impairments recognized in earnings	150	1,698
Changes in assets and liabilities:
Reinsurance recoverable on paid and unpaid losses and loss adjustment expenses	(2,225)	55,436
Reserves for losses and loss adjustment expenses	65,483	15,683
Prepaid reinsurance premiums	9,697	(14,637)
Unearned premiums	77,299	81,237
Premiums receivable	(43,813)	(735)
Deferred policy acquisition costs	(24,312)	(9,507)
Accrued investment income	(839)	(1,338)
Reinsurance balances payable	16,291	(18,993)
Current income tax payable, net	5,101	411
Other	31,047	(6,679)
Net cash provided by (used in) operating activities	187,019	159,144
Fixed maturities
Redemptions and maturities	207,620	126,930
Sales	370,501	266,707
Purchases	(776,086)	(446,516)
Equity securities
Sales	36,918	76,388
Purchases	(58,405)	(178,517)
Change in payable for securities	41,265	28,465
Purchase of other invested assets	(2,021)
Net change in short-term investments	84,022	(53,747)
Purchase of property and equipment	(3,571)	(1,503)
Net cash provided by (used in) investing activities	(99,757)	(181,793)
Financing activities:
Proceeds of stock issued from employee stock purchase plan	1,840	1,352
Proceeds of stock issued from exercise of stock options		29
Dividends paid	(2,619)
Net cash provided by (used in) financing activities	(779)	1,381
Effect of exchange rate on cash	(8,869)
Change in cash	77,614	(21,268)
Cash at beginning of year	69,901	90,751
Cash at end of period	147,515	69,483
Supplemental information:
Income taxes paid, net	24,148	28,634
Interest paid	7,619	7,619
Issuance of stock to directors	$ 633	$ 563

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	NOTE 1. ORGANIZATION & SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Unless the context requires otherwise, the terms “we,” “us,” “our,” or “our Company” are used to mean The Navigators Group, Inc., a Delaware holding company established in 1982, and its subsidiaries. The term “Parent Company” is used to mean The Navigators Group, Inc. without its subsidiaries. Organization We are an international insurance company with a long-standing area of specialization in Marine insurance. We also offer Property and Casualty (“P&C”) insurance business, primarily general liability coverage and umbrella & excess liability coverage to commercial enterprises through our Primary and Excess Casualty divisions. We have also developed niches in Professional Liability insurance, through our Directors & Officers (“D&O”) and Errors & Omissions (“E&O”) divisions. Beginning in 2010, we added reinsurance products through our Global Reinsurance (“GlobalRe”) business. We operate through various wholly-owned subsidiaries, including Navigators Insurance Company (“NIC”), inclusive of its United Kingdom Branch (“U.K. Branch”), and Navigators Specialty Insurance Company (“NSIC”), both of which are U.S. insurance companies, and Navigators Underwriting Agency Ltd. (“NUAL”), a Lloyd’s of London (“Lloyd’s”) underwriting agency that manages Lloyd’s Syndicate 1221 (the “Syndicate”) in the U.K. and is the primary underwriting company of Navigators Holdings (U.K.) Ltd. (“NHUK”), the holding company for our non U.S. domiciled entities. Our Company controls 100% of the Syndicate’s stamp capacity. Basis of Presentation The accompanying Interim Consolidated Financial Statements are unaudited and reflect all adjustments, which, in the opinion of management, are necessary to fairly present the results of The Navigators Group, Inc. and its subsidiaries for the interim periods presented on the basis of United States generally accepted accounting principles (“GAAP” or “U.S. GAAP”). All significant intercompany transactions and balances have been eliminated in consolidation. The preparation of these Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the Financial Statements and the reported revenues and expenses during the reporting periods. The results of operations for any interim period are not necessarily indicative of results for the full year. The Interim Consolidated Financial Statements should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2015. Certain amounts for the prior period have been reclassified to conform with the current period presentation. Income Taxes The interim income tax provision has been computed based on our estimated annual Effective tax rate, which represents our best estimate on a year to date basis for the interim period. As a result, the tax provision for a given quarter equals the difference between the provision recorded cumulatively year to date less the amount recorded cumulatively as of the end of the prior interim period. Our Effective tax rate for the quarter and year to date differs from the federal tax rate of 35% primarily due to tax-exempt investment income and dividends received deduction. Current and Pending Accounting Pronouncements As of January 1, 2016, we adopted the following accounting pronouncements, which did not have a material effect, singly or in the aggregate, on our Consolidated Financial Statements: • Accounting Standards Update 2015-03 – Interest – Imputation of Interest (Subtopic 835-30) – Simplifying the Presentation of Debt Issuance Costs, which is effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to simplify presentation of debt issuance costs. • Accounting Standards Update 2015-05 – Intangibles – Goodwill and Other – Internal Use Software (Subtopic 350-40) Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement, which is effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to provide guidance to customers about whether a cloud computing arrangement includes a software license. • Accounting Standards Update 2015-07 – Fair Value Measurement – (Topic 820) Disclosures for Investments in Certain Entities that Calculate Net Asset Value per Share (or its equivalent) (a consensus of the Emerging Issues Task Force), which is effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to ensure that all investments categorized in the fair value hierarchy are classified using a consistent approach. In 2016, the Financial Accounting Standards Board issued the following new pronouncements that may have an impact on our Company and we are assessing the future impact of these updates on our Consolidated Financial Statements: • Accounting Standards Update 2016-01 – Financial Instruments (Subtopic 825-10) – Recognition and Measurement of Financial Assets and Financial Liabilities, which will be effective for fiscal years beginning after December 15, 2017. The new pronouncement was issued to make targeted improvements to the presentation of financial instruments. • Accounting Standards Update 2016-02 – Leases (Topic 842) – Amends the recognition of a right-to-use asset and lease liability on the statement of financial position of those leases previously classified as operating leases under the previous guidance, which will be effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to improve transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. • Accounting Standards Update 2016-09 – Compensation – Stock Compensation – (Topic 718) – Improvements to Employee Share-Based Accounting, which will be effective for fiscal years beginning after December 15, 2016. The new pronouncement was issued to simplify employee share-based accounting. • Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326) – amends the measurement of credit losses on financial instruments not accounted for at fair value including loans, debt securities, reinsurance receivables and any other financial assets, which will be effective for the fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. • Accounting Standards Update 2016-15 – Statements of Cash Flows (Topic 230) – Classification of Certain Cash Receipts and Cash Payments amends how certain cash receipts and cash payments are presented in the statement of cash flows to reduce existing diversity in practice. There were no additional 2016 accounting pronouncements that are expected to have an impact on the Consolidated Financial Statements upon adoption.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Segment Information	NOTE 2. SEGMENT INFORMATION We report our results of operations consistent with the manner in which our Chief Operating Decision Maker reviews the business to assess performance through our reporting segments: U.S. Insurance, International Insurance (“Int’l Insurance”), GlobalRe and Corporate. We classify our business into three underwriting segments: U.S. Insurance, Int’l Insurance and GlobalRe. Both the U.S. Insurance and Int’l Insurance reporting segments are each comprised of three operating segments: Marine, P&C and Professional Liability. We evaluate the performance of each of the underwriting segments based on underwriting results. Underwriting results are measured based on underwriting profit or loss and the related Combined ratio, which are both non-GAAP measures of underwriting profitability. Underwriting profit (loss) is calculated from Net earned premiums less the sum of Net losses and loss adjustment expenses (“LAE”), Commission expenses, Other operating expenses and Other underwriting income (expense). The Combined ratio is derived by dividing the sum of Net losses and LAE, Commission expenses, Other operating expenses and Other underwriting income (expense) by Net earned premiums. A Combined ratio of less than 100% indicates an underwriting profit and greater than 100% indicates an underwriting loss. Our underwriting performance is evaluated separately from the rest of our operations. The performance of our investment portfolios, our liquidity and capital resource needs, our foreign currency exposure and our tax planning strategies are evaluated on a consolidated basis within our Corporate segment. The accounting policies used to prepare the segment reporting data for our reporting segments are the same as those described in Note 1 and Note 2 of our Annual Report on Form 10-K for the year ended December 31, 2015. Financial data by segment for the three and nine months ended September 30, 2016 and 2015 was as follows: Three Months Ended September 30, 2016 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 161,722 $ 79,761 $ 42,527 $ — $ 284,010 Net losses and LAE (106,320 ) (45,043 ) (21,430 ) — (172,793 ) Commission expenses (18,630 ) (15,348 ) (8,951 ) 318 (42,611 ) Other operating expenses (31,517 ) (20,183 ) (4,437 ) — (56,137 ) Other underwriting income (expense) 240 — 122 (318 ) 44 Underwriting profit (loss) $ 5,495 $ (813 ) $ 7,831 $ — $ 12,513 Net investment income 19,875 19,875 Net realized gains (losses) 1,586 1,586 Interest expense (3,859 ) (3,859 ) Other income (loss) (227 ) (227 ) Income before income taxes $ 5,495 $ (813 ) $ 7,831 $ 17,375 $ 29,888 Income tax (expense) benefit (7,875 ) (7,875 ) Net income (loss) $ 22,013 Losses and LAE ratio 65.7 % 56.5 % 50.4 % 60.8 % Commission expense ratio 11.5 % 19.2 % 21.0 % 15.0 % Other operating expense ratio (2) 19.4 % 25.3 % 10.2 % 19.8 % Combined ratio 96.6 % 101.0 % 81.6 % 95.6 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense). Three Months Ended September 30, 2015 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 142,409 $ 68,533 $ 43,140 $ — $ 254,082 Net losses and LAE (85,140 ) (39,182 ) (22,224 ) — (146,546 ) Commission expenses (15,157 ) (12,780 ) (7,705 ) 1,389 (34,253 ) Other operating expenses (32,948 ) (19,937 ) (3,714 ) — (56,599 ) Other underwriting income (expense) 1,013 — 395 (1,389 ) 19 Underwriting profit (loss) $ 10,177 $ (3,366 ) $ 9,892 $ — $ 16,703 Net investment income 17,371 17,371 Net realized gains (losses) (757 ) (757 ) Interest expense (3,856 ) (3,856 ) Other income (loss) (2,537 ) (2,537 ) Income before income taxes $ 10,177 $ (3,366 ) $ 9,892 $ 10,221 $ 26,924 Income tax (expense) benefit (8,723 ) (8,723 ) Net income (loss) $ 18,201 Losses and LAE ratio 59.8 % 57.2 % 51.5 % 57.7 % Commission expense ratio 10.6 % 18.6 % 17.9 % 13.5 % Other operating expense ratio (2) 22.5 % 29.1 % 7.7 % 22.2 % Combined ratio 92.9 % 104.9 % 77.1 % 93.4 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense). Nine Months Ended September 30, 2016 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 462,446 $ 235,602 $ 118,312 $ — $ 816,360 Net losses and LAE (291,260 ) (133,519 ) (68,176 ) — (492,955 ) Commission expenses (50,379 ) (47,524 ) (24,188 ) 1,200 (120,891 ) Other operating expenses (96,848 ) (64,997 ) (14,175 ) — (176,020 ) Other underwriting income (expense) 943 — 374 (1,200 ) 117 Underwriting profit (loss) $ 24,902 $ (10,438 ) $ 12,147 $ — $ 26,611 Net investment income 59,344 59,344 Net realized gains (losses) 4,993 4,993 Interest expense (11,575 ) (11,575 ) Other income (loss) 6,679 6,679 Income (loss) before income taxes $ 24,902 $ (10,438 ) $ 12,147 $ 59,441 $ 86,052 Income tax (expense) benefit (24,917 ) (24,917 ) Net income (loss) $ 61,135 Losses and LAE ratio 63.0 % 56.7 % 57.6 % 60.4 % Commission expense ratio 10.9 % 20.2 % 20.4 % 14.8 % Other operating expense ratio (2) 20.7 % 27.5 % 11.7 % 21.5 % Combined ratio 94.6 % 104.4 % 89.7 % 96.7 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense). Nine Months Ended September 30, 2015 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 410,804 $ 197,244 $ 124,494 $ — $ 732,542 Net losses and LAE (247,094 ) (101,236 ) (70,387 ) — (418,717 ) Commission expenses (41,777 ) (35,491 ) (23,042 ) 1,672 (98,638 ) Other operating expenses (98,010 ) (54,312 ) (11,975 ) — (164,297 ) Other underwriting income (expense) 1,330 — 441 (1,672 ) 99 Underwriting profit (loss) $ 25,253 $ 6,205 $ 19,531 $ — $ 50,989 Net investment income 50,219 50,219 Net realized gains (losses) 8,755 8,755 Interest expense (11,567 ) (11,567 ) Other income (loss) (4,737 ) (4,737 ) Income (loss) before income taxes $ 25,253 $ 6,205 $ 19,531 $ 42,670 $ 93,659 Income tax (expense) benefit (30,345 ) (30,345 ) Net income (loss) $ 63,314 Losses and LAE ratio 60.1 % 51.3 % 56.5 % 57.2 % Commission expense ratio 10.2 % 18.0 % 18.5 % 13.5 % Other operating expense ratio (2) 23.6 % 27.6 % 9.3 % 22.3 % Combined ratio 93.9 % 96.9 % 84.3 % 93.0 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense). Revenue by operating segment for the three and nine months ended September 30, 2016 and 2015 was as follows: Three Months Ended September 30, 2016 Three Months Ended September 30, 2015 % Change amounts in thousands Gross written premiums Ceded written premiums Net premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums U.S. Insurance Marine $ 40,271 $ (17,636 ) $ 22,635 $ 25,465 $ 35,529 $ (13,865 ) $ 21,664 $ 24,292 13.3 % 27.2 % 4.5 % 4.8 % P&C 161,600 (36,011 ) 125,589 115,971 154,009 (34,902 ) 119,107 104,473 4.9 % 3.2 % 5.4 % 11.0 % Professional 32,776 (7,712 ) 25,064 20,286 29,245 (14,986 ) 14,259 13,644 12.1 % (48.5 %) 75.8 % 48.7 % Total $ 234,647 $ (61,359 ) $ 173,288 $ 161,722 $ 218,783 $ (63,753 ) $ 155,030 $ 142,409 7.3 % (3.8 %) 11.8 % 13.6 % Int'l Insurance Marine $ 38,453 $ (12,631 ) $ 25,822 $ 34,794 $ 41,002 $ (10,985 ) $ 30,017 $ 36,792 (6.2 %) 15.0 % (14.0 %) (5.4 %) P&C 38,077 (15,331 ) 22,746 25,584 37,449 (20,034 ) 17,415 16,879 1.7 % (23.5 %) 30.6 % 51.6 % Professional Liability 27,954 (7,232 ) 20,722 19,383 20,337 (6,785 ) 13,552 14,862 37.5 % 6.6 % 52.9 % 30.4 % Total $ 104,484 $ (35,194 ) $ 69,290 $ 79,761 $ 98,788 $ (37,804 ) $ 60,984 $ 68,533 5.8 % (6.9 %) 13.6 % 16.4 % GlobalRe $ 35,799 $ (1,376 ) $ 34,423 $ 42,527 $ 36,491 $ (566 ) $ 35,925 $ 43,140 (1.9 %) 143.2 % (4.2 %) (1.4 %) Total $ 374,930 $ (97,929 ) $ 277,001 $ 284,010 $ 354,062 $ (102,123 ) $ 251,939 $ 254,082 5.9 % (4.1 %) 9.9 % 11.8 % Nine Months Ended September 30, 2016 Nine Months Ended September 30, 2015 % Change amounts in thousands Gross written premiums Ceded written premiums Net premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums U.S. Insurance Marine $ 129,621 $ (53,823 ) $ 75,798 $ 73,636 $ 118,167 $ (45,177 ) $ 72,990 $ 74,193 9.7 % 19.1 % 3.8 % (0.7 %) P&C 471,532 (103,286 ) 368,246 335,342 458,371 (123,765 ) 334,606 291,648 2.9 % (16.5 %) 10.1 % 15.0 % Professional 88,065 (21,365 ) 66,700 53,468 81,559 (42,423 ) 39,136 44,963 8.0 % (49.6 %) 70.4 % 18.9 % Total $ 689,218 $ (178,474 ) $ 510,744 $ 462,446 $ 658,097 $ (211,365 ) $ 446,732 $ 410,804 4.7 % (15.6 %) 14.3 % 12.6 % Int'l Insurance Marine $ 151,548 $ (33,274 ) $ 118,274 $ 109,746 $ 149,844 $ (30,933 ) $ 118,911 $ 114,716 1.1 % 7.6 % (0.5 %) (4.3 %) P&C 145,125 (57,025 ) 88,100 70,608 112,014 (60,676 ) 51,338 43,112 29.6 % (6.0 %) 71.6 % 63.8 % Professional 87,694 (21,776 ) 65,918 55,248 68,147 (22,072 ) 46,075 39,416 28.7 % (1.3 %) 43.1 % 40.2 % Total $ 384,367 $ (112,075 ) $ 272,292 $ 235,602 $ 330,005 $ (113,681 ) $ 216,324 $ 197,244 16.5 % (1.4 %) 25.9 % 19.4 % GlobalRe $ 127,787 $ (7,467 ) $ 120,320 $ 118,312 $ 141,891 $ (5,806 ) $ 136,085 $ 124,494 (9.9 %) 28.6 % (11.6 %) (5.0 %) Total $ 1,201,372 $ (298,016 ) $ 903,356 $ 816,360 $ 1,129,993 $ (330,852 ) $ 799,141 $ 732,542 6.3 % (9.9 %) 13.0 % 11.4 %

Investments

Investments	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Investments	NOTE 3. INVESTMENTS The following tables set forth our Company’s investments as of September 30, 2016 and December 31, 2015 and include Other-than-temporary-impairment (“OTTI”) securities recognized within Accumulated other comprehensive income (“AOCI”): September 30, 2016 Gross Gross Cost or Fair Unrealized Unrealized Amortized amounts in thousands Value Gains (Losses) Cost Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 262,030 $ 3,691 $ (3,981 ) $ 262,320 States, municipalities and political subdivisions 580,324 29,288 (769 ) 551,805 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 526,069 11,778 (105 ) 514,396 Residential mortgage obligations 27,055 455 (97 ) 26,697 Asset-backed securities 288,636 1,503 (458 ) 287,591 Commercial mortgage-backed securities 165,405 6,392 (423 ) 159,436 Subtotal $ 1,007,165 $ 20,128 $ (1,083 ) $ 988,120 Corporate bonds 810,898 23,447 (1,354 ) 788,805 Total fixed maturities $ 2,660,417 $ 76,554 $ (7,187 ) $ 2,591,050 Equity securities 342,677 38,538 (1,767 ) 305,906 Other invested assets 2,021 — — 2,021 Short-term investments 134,273 — — 134,273 Total investments $ 3,139,388 $ 115,092 $ (8,954 ) $ 3,033,250 December 31, 2015 Gross Gross Cost or Fair Unrealized Unrealized Amortized amounts in thousands Value Gains (Losses) Cost Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 252,882 $ 2,273 $ (9,214 ) $ 259,823 States, municipalities and political subdivisions 576,859 21,233 (781 ) 556,407 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 379,269 5,573 (2,082 ) 375,778 Residential mortgage obligations 30,465 694 (82 ) 29,853 Asset-backed securities 225,012 85 (1,624 ) 226,551 Commercial mortgage-backed securities 189,713 3,119 (1,864 ) 188,458 Subtotal $ 824,459 $ 9,471 $ (5,652 ) $ 820,640 Corporate bonds 760,010 7,373 (10,738 ) 763,375 Total fixed maturities $ 2,414,210 $ 40,350 $ (26,385 ) $ 2,400,245 Equity securities 305,271 26,341 (3,013 ) 281,943 Short-term investments 217,745 2 — 217,743 Total investments $ 2,937,226 $ 66,693 $ (29,398 ) $ 2,899,931 As of September 30, 2016 and December 31, 2015, our Company did not have a concentration of greater than 5% of invested assets in a single non-government backed issuer. During the third quarter of 2016, the Company made investments in certain companies, which are reported as Other invested assets on the Consolidated Balance Sheet and accounted for using the equity method. Our initial estimate of the net asset value of these investments is the transaction price. We believe the net asset value to be a practical expedient for the fair value of these investments. As of September 30, 2016 and December 31, 2015, Fixed maturities for which non-credit OTTI was previously recognized and included in AOCI are now in a net unrealized net gains position of $0.4 million and $0.5 million, respectively. The fair value of our Company’s investment portfolio may fluctuate significantly in response to various factors such as changes in interest rates, investment quality ratings, equity prices, foreign exchange rates and credit spreads. Our Company does not have the intent to sell nor is it more likely than not that it will have to sell Fixed maturities in unrealized loss positions that are not other-than-temporarily impaired before recovery. For structured securities, default probability and severity assumptions differ based on property type, vintage and the stress of the collateral. Our Company does not intend to sell, and it is more likely than not that our Company will not be required to sell, these securities before the recovery of the amortized cost basis. For Equity securities, our Company also considers our intent to hold securities as part of the process of evaluating whether a decline in fair value represents an other-than-temporary decline in value. Our Company may realize investment losses to the extent our liquidity needs require the disposition of Fixed maturity securities in unfavorable interest rate, liquidity or credit spread environments. Significant changes in the factors our Company considers when evaluating investments for impairment losses could result in a significant change in impairment losses reported in the Consolidated Financial Statements. The contractual maturity dates for Fixed maturities categorized by the number of years until maturity as of September 30, 2016 are shown in the following table: September 30, 2016 Fair Amortized amounts in thousands Value Cost Due in one year or less $ 81,849 $ 83,551 Due after one year through five years 810,165 799,159 Due after five years through ten years 296,471 281,368 Due after ten years 464,767 438,852 Mortgage-backed and asset-backed securities 1,007,165 988,120 Total $ 2,660,417 $ 2,591,050 Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Prepayment assumptions associated with the mortgage-backed and asset-backed securities are reviewed on a periodic basis. When changes in prepayment assumptions are deemed necessary as the result of actual prepayments differing from anticipated prepayments, securities are revalued based upon the new prepayment assumptions utilizing the retrospective accounting method. Due to the periodic repayment of principal, the mortgage-backed and asset-backed securities are estimated to have an effective maturity of approximately 4.1 years. The following tables summarize all securities in a gross unrealized loss position as of September 30, 2016 and December 31, 2015, showing the aggregate fair value and gross unrealized loss by the length of time those securities have continuously been in a gross unrealized loss position: September 30, 2016 Less than 12 months Greater than 12 months Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized amounts in thousands Value (Losses) Value (Losses) Value (Losses) Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 91,676 $ (969 ) $ 19,897 $ (3,012 ) $ 111,573 $ (3,981 ) States, municipalities and political subdivisions 49,881 (593 ) 9,932 (176 ) 59,813 (769 ) Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 52,754 (17 ) 13,547 (88 ) 66,301 (105 ) Residential mortgage obligations 1,317 (16 ) 1,631 (81 ) 2,948 (97 ) Asset-backed securities 22,422 (158 ) 61,499 (300 ) 83,921 (458 ) Commercial mortgage-backed securities 20,864 (38 ) 8,854 (385 ) 29,718 (423 ) Subtotal $ 97,357 $ (229 ) $ 85,531 $ (854 ) $ 182,888 $ (1,083 ) Corporate bonds 120,114 (622 ) 23,053 (732 ) 143,167 (1,354 ) Total fixed maturities $ 359,028 $ (2,413 ) $ 138,413 $ (4,774 ) $ 497,441 $ (7,187 ) Equity securities 38,050 (1,490 ) 4,723 (277 ) 42,773 (1,767 ) Total fixed maturities and equity securities $ 397,078 $ (3,903 ) $ 143,136 $ (5,051 ) $ 540,214 $ (8,954 ) December 31, 2015 Less than 12 months Greater than 12 months Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized amounts in thousands Value (Losses) Value (Losses) Value (Losses) Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 142,233 $ (3,032 ) $ 22,230 $ (6,182 ) $ 164,463 $ (9,214 ) States, municipalities and political subdivisions 50,577 (549 ) 4,808 (232 ) 55,385 (781 ) Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 164,817 (1,315 ) 29,862 (767 ) 194,679 (2,082 ) Residential mortgage obligations 3,910 (5 ) 1,684 (77 ) 5,594 (82 ) Asset-backed securities 112,479 (663 ) 81,477 (961 ) 193,956 (1,624 ) Commercial mortgage-backed securities 83,024 (1,826 ) 3,065 (38 ) 86,089 (1,864 ) Subtotal $ 364,230 $ (3,809 ) $ 116,088 $ (1,843 ) $ 480,318 $ (5,652 ) Corporate bonds 395,399 (10,114 ) 13,849 (624 ) 409,248 (10,738 ) Total fixed maturities $ 952,439 $ (17,504 ) $ 156,975 $ (8,881 ) $ 1,109,414 $ (26,385 ) Equity securities 58,531 (3,013 ) — — 58,531 (3,013 ) Total fixed maturities and equity securities $ 1,010,970 $ (20,517 ) $ 156,975 $ (8,881 ) $ 1,167,945 $ (29,398 ) As of September 30, 2016, there were 177 Fixed maturities and 42 Equity securities in an unrealized loss position. As of December 31, 2015, there were 368 Fixed maturities and 57 Equity securities in an unrealized loss position. As of September 30, 2016 and December 31, 2015, the gross unrealized loss for the greater than 12 months category consists primarily of agency and foreign government bonds principally due to an unfavorable foreign exchange movement. The gross unrealized losses for the less than 12 months category for the period ended September 30, 2016 is broadly spread across our common equity portfolio and to a lesser extent, agency and foreign government bonds due to an unfavorable exchange movement. The gross unrealized loss for the less than 12 months category for the period ended December 31, 2015 consists primarily of Corporate bonds in the energy sector, which have been impacted by the recent decline in oil prices. As of September 30, 2016 and December 31, 2015, the largest unrealized loss by a non-government backed issuer in the investment portfolio was $0.4 million and $2.6 million, respectively. Our Company analyzes impaired securities quarterly to determine if any are other-than-temporary. The above securities with unrealized losses have been determined to be temporarily impaired based on our evaluation. Our Company reviews the magnitude of a security’s unrealized loss compared to its cost/amortized cost and the length of time that the security has been impaired to determine if an unrealized loss is other-than-temporary. If warranted as a result of conditions relating to a particular security, our Company will also review securities with declines in fair value resulting from a headline news event involving the issuer, a headline news event involving the asset class, the advice of our external asset managers, or economic events that may impact the issuer to determine if an unrealized loss is other-than-temporary. The depth of analysis performed is dependent upon the nature and magnitude of the indicators of other-than-temporary impairment present in regards to each impaired security. For Equity securities, our Company performs a fundamental analysis of the issuer, including an evaluation of the mean analysts’ target price, to assess the likelihood of recovery of our cost basis in the security. Management also assesses the likelihood of future cash flows, dividends and increases to dividends, all of which affect the securities eligibility for our equity strategy and therefore our intent to hold the security. If an equity security is deemed to be other-than-temporarily-impaired, the cost is written down to fair value with the loss recognized in earnings. For Fixed maturities, our Company assesses the underlying fundamentals of each issuer to determine if there is a change in the amount or timing of expected cash flows. Management compares the amortized cost basis to the present value of the revised cash flows using the historical book yield to determine the credit loss portion of impairment which is recognized in earnings. All non-credit losses where we have the intent and ability to hold the security until recovery are recognized as changes in OTTI losses within AOCI. Specifically for structured Fixed maturities, our Company analyzes projections provided by our investment managers with respect to an expected principal loss under a range of scenarios and utilizes the most likely outcomes. The analysis relies on actual collateral performance measures such as default rate, prepayment rate and loss severity. These assumptions are applied throughout the remaining term of the deal, incorporating the transaction structure and priority of payments, to generate loss adjusted cash flows. Results of the analysis will indicate whether the security is expected ultimately to incur a loss or whether there is a material impact on yield due to either a projected loss or a change in cash flow timing. A break-even default rate is also calculated. A comparison of the break-even default rate to the actual default rate provides an indication of the level of cushion or coverage to the first dollar principal loss. For securities in which a tranche loss is present and the net present value of loss adjusted cash flows is less than book value, credit impairment is recognized in earnings. The output data also includes a number of additional metrics such as average life remaining, original and current credit support, over 60 day delinquency and security rating. The significant inputs used to measure the amount of credit loss recognized in earnings were actual delinquency rates, default probability, severity and prepayment assumptions. Projected losses are a function of both loss severity and probability of default, which differ based on property type, vintage and the stress of the collateral. Our Company’s ability to hold securities is supported by sufficient cash flow from our operations and from maturities within our investment portfolio in order to meet our claims payments and other disbursement obligations arising from our underwriting operations without selling such investments. With respect to securities where the decline in value is determined to be temporary and the security’s value is not written down, a subsequent decision may be made to sell that security and realize a loss. Subsequent decisions on security sales are made within the context of overall risk monitoring, changing information and market conditions. As of September 30, 2016, our Company does not intend to sell, and it is more-likely-than-not that it will not be required to sell any of its securities with unrealized losses before they recover in value. Our Company had no credit related OTTI losses during the three months ended September 30, 2016. Our Company had one credit related OTTI loss of $0.2 million in the Fixed maturities portfolio during the nine months ended September 30, 2016. Our Company had three credit related losses totaling $1.3 million and $1.7 million in the equity portfolio during the three and nine months ended September 30, 2015, respectively. The following table summarizes the cumulative amounts related to our Company’s credit loss portion of the OTTI losses on Fixed maturities for the three and nine months ended September 30, 2016 and 2015: Three Months Ended September 30, Nine Months Ended September 30, amounts in thousands 2016 2015 2016 2015 Beginning balance $ 2,511 $ 2,361 $ 2,361 $ 2,361 Additions for credit loss impairments recognized in the current period on securities not previously impaired — — 150 — Additions for credit loss impairments recognized in the current period on securities previously impaired — — — — Reductions for credit loss impairments previously recognized on securities sold during the period (150 ) — (150 ) — Ending balance $ 2,361 $ 2,361 $ 2,361 $ 2,361 Our Company’s Net investment income was derived from the following sources: Three Months Ended September 30, Nine Months Ended September 30, amounts in thousands 2016 2015 2016 2015 Fixed maturities $ 17,124 $ 15,353 $ 50,781 $ 45,660 Equity securities 3,540 2,543 10,418 6,383 Short-term investments 70 272 568 604 Total investment income $ 20,734 $ 18,168 $ 61,767 $ 52,647 Investment expenses (859 ) (797 ) (2,423 ) (2,428 ) Net investment income $ 19,875 $ 17,371 $ 59,344 $ 50,219 Realized gains and losses, excluding net OTTI losses recognized in earnings, for the periods indicated, were as follows: Three Months Ended September 30, Nine Months Ended September 30, amounts in thousands 2016 2015 2016 2015 Fixed maturities: Gains $ 1,356 $ 484 $ 5,200 $ 2,889 Losses (1,221 ) (667 ) (3,086 ) (2,757 ) Fixed maturities, net $ 135 $ (183 ) $ 2,114 $ 132 Short-term: Gains $ 128 $ 9 $ 803 $ 109 Losses (107 ) (120 ) (250 ) (273 ) Short-term, net $ 21 $ (111 ) $ 553 $ (164 ) Equity securities: Gains $ 1,443 $ 1,107 $ 3,123 $ 12,185 Losses (13 ) (295 ) (647 ) (1,700 ) Equity securities, net $ 1,430 $ 812 $ 2,476 $ 10,485 Net realized gains (losses) $ 1,586 $ 518 $ 5,143 $ 10,453

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurement	NOTE 4. FAIR VALUE MEASUREMENT The fair value of our financial instruments is determined based on the following fair value hierarchy: Level 1 – Quoted prices for identical instruments in active markets. Examples are listed equity and fixed income securities traded on an exchange. U.S. Treasury securities are reported as Level 1 and are valued based on unadjusted quoted prices for identical assets in active markets that our Company can access. Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. Examples are asset-backed and mortgage-backed securities that are similar to other asset-backed or mortgage-backed securities observed in the market. U.S. government agency securities are reported as Level 2 and are valued using yields and spreads that are observable in active markets. Level 3 – Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. An example would be a private placement with minimal liquidity. Other invested assets are measured at net asset value as a practical expedient for fair value. The following tables present, for each of the fair value hierarchy levels as defined by the accounting guidance for fair value measurements and described above, our Company’s Fixed maturities and Equity securities by asset class that are measured at fair value on a recurring basis, as well as the fair value of the 5.75% Senior notes due October 15, 2023 (the “Senior notes”) carried at amortized cost as of September 30, 2016 and December 31, 2015: September 30, 2016 amounts in thousands Level 1 Level 2 Level 3 Fair Value based on net asset value Total Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 55,159 $ 206,871 $ — $ — $ 262,030 States, municipalities and political subdivisions — 580,324 — — 580,324 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities — 526,069 — — 526,069 Residential mortgage obligations — 27,055 — — 27,055 Asset-backed securities — 288,636 — — 288,636 Commercial mortgage-backed securities — 165,405 — — 165,405 Subtotal $ — $ 1,007,165 $ — $ — $ 1,007,165 Corporate bonds — 810,898 — — 810,898 Total fixed maturities $ 55,159 $ 2,605,258 $ — $ — $ 2,660,417 Equity securities 158,963 183,714 — 342,677 Other invested assets — — — 2,021 2,021 Short-term investments 134,273 — — — 134,273 Total assets measured at fair value $ 348,395 $ 2,788,972 $ — $ 2,021 $ 3,139,388 Senior notes $ — $ 294,080 $ — $ — $ 294,080 Total liabilities measured at fair value $ — $ 294,080 $ — $ — $ 294,080 December 31, 2015 amounts in thousands Level 1 Level 2 Level 3 Total Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 67,394 $ 185,488 $ — $ 252,882 States, municipalities and political subdivisions — 576,859 — 576,859 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities — 379,269 — 379,269 Residential mortgage obligations — 30,465 — 30,465 Asset-backed securities — 225,012 — 225,012 Commercial mortgage-backed securities — 189,713 — 189,713 Subtotal $ — $ 824,459 $ — $ 824,459 Corporate bonds — 760,010 — 760,010 Total fixed maturities $ 67,394 $ 2,346,816 $ — $ 2,414,210 Equity securities 126,455 178,816 — 305,271 Short-term investments 217,745 — — 217,745 Total assets measured at fair value $ 411,594 $ 2,525,632 $ — $ 2,937,226 Senior notes $ — $ 282,486 $ — $ 282,486 Total liabilities measured at fair value $ — $ 282,486 $ — $ 282,486 All other financial assets and liabilities including Cash, Premium receivable, Reinsurance recoverable and Reinsurance balances payable are carried at cost, which approximates fair value Our Company did not have any significant transfers between Level 1 and Level 2 classifications for the three and nine months ended September 30, 2016 and 2015. As of September 30, 2016, our Company did not have any Level 3 assets.

Ceded Reinsurance

Ceded Reinsurance	9 Months Ended
	Sep. 30, 2016
Insurance [Abstract]
Ceded Reinsurance	NOTE 5. CEDED REINSURANCE As of September 30, 2016, the credit quality distribution of our Company’s Reinsurance recoverable of $1.1 billion for ceded paid losses, ceded unpaid losses and LAE, and ceded unearned premiums based on insurer financial strength ratings from A.M. Best or S&P was not significantly different from the credit quality distribution as of December 31, 2015. Our allowance for uncollectible reinsurance was $10.4 million as of September 30, 2016 and $6.9 million as of December 31, 2015. The increase is primarily due to lower expectations of recoveries from a reinsurer. As of September 30, 2016, our 10 largest reinsurers measured by the amount of Reinsurance recoverable for ceded losses and LAE and ceded unearned premium, together with the reinsurance recoverable and collateral, were not significantly different from December 31, 2015.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 6. COMMITMENTS AND CONTINGENCIES In 2013, the State of Connecticut (“the State”) awarded our Company up to $11.5 million ($8.0 million in loans and $3.5 million in grants) to move our corporate headquarters to Stamford, Connecticut. The loan is non-interest bearing, has a term of 10 years and is subject to forgiveness based on our compliance with certain conditions set forth in the agreement with the State. The amount of the loan to be received is dependent on our Company reaching certain milestones for creation of new jobs over a five-year period, and the funds are to be used to offset certain equipment purchases, facility costs, training of employees and other eligible project-related costs. Our Company completed the move to Stamford in September 2013 and received $7.5 million of the award, which is comprised of $6.0 million of the loan and $1.5 million of the grant for reaching the first job milestone. Under the terms of the agreement with the State, our Company was required to maintain an average of 100 full-time employees in Connecticut over a 12-month period in order for the State to forgive the initial $6.0 million of the loan. In addition, as soon as our Company achieved a total of 150 full-time employees in Connecticut, we became eligible to receive an additional $1.0 million of the loan and $0.5 million of the grant. On October 20, 2015, our Company received a letter from the State determining that we had achieved both of these milestones. As a result, our Company earned a loan forgiveness credit of $6.0 million with the State and received the additional $1.0 million of the loan and $0.5 million of the grant. Earning of the remaining portions of the grant and forgiveness of any outstanding amounts of the loan is subject to certain conditions, including maintaining a certain number of required jobs for an extended period of time. Our Company expects to meet all the conditions for the State to forgive the loan. Accordingly, our Company is recognizing the amount of loan and grants received over the period in which offsetting expenses are recognized. Our Company recognized $0.4 million and $1.1 million of the incentive for the three and nine months ended September 30, 2016. As of September 30, 2016 and December 31, 2015, our Company has deferred revenue of $5.1 million and $6.3 million, respectively, which is included in Other liabilities on the Consolidated Balance Sheets. In the ordinary course of conducting business, our Company’s subsidiaries are involved in various legal proceedings, either indirectly as insurers for parties to the proceedings or directly as defendants. Most of these proceedings consist of claims litigation involving our Company’s subsidiaries as either: (a) liability insurers defending or providing indemnity for third party claims brought against insureds or (b) insurers defending first party coverage claims brought against them. Our Company accounts for such activity through the establishment of unpaid losses and LAE reserves. Our Company’s management believes that the ultimate liability, if any, with respect to such ordinary-course claims litigation, after consideration of provisions made for potential losses and cost of defense, will not be material to our Company’s Consolidated Balance Sheets, Consolidated Statements of Income or Consolidated Statements of Cash Flows. Our Company’s subsidiaries are also from time to time involved with other legal actions, some of which assert claims for substantial amounts. These actions include claims asserting extra contractual obligations, such as claims involving allegations of bad faith in the handling of claims or the underwriting of policies. In general, our Company believes it has valid defenses to these cases. Our Company’s management expects that the ultimate liability, if any, with respect to future extra-contractual matters will not be material to our Consolidated Balance Sheets, Consolidated Statements of Income or Consolidated Statements of Cash Flows. Nonetheless, given the large or indeterminate amounts sought in certain of these matters, and the inherent unpredictability of litigation, an adverse outcome in such matters could, from time to time, have a material adverse effect on our Company’s Consolidated Statements of Income or Consolidated Statements of Cash Flows in a particular fiscal quarter or year.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	NOTE 7. STOCK-BASED COMPENSATION Stock-based compensation granted under our Company’s stock plans is expensed in tranches over the vesting period. Options and non-performance based grants generally vest equally over a three or four-year period and the options have a maximum term of ten years. For the nine months ended September 30, 2016, we granted 216,973 stock incentive units at a grant price between $80.98 and $92.56. Each performance unit and restricted stock unit represents a contingent right to receive one share of common stock as of the vesting date. Such common stock may be subject to forfeiture for the payment of any required tax withholding.

Stockholders Equity

Stockholders Equity	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Stockholders' Equity	NOTE 8. STOCKHOLDERS’ EQUITY On May 26, 2016, our Board of Directors declared its intention to pay a regular quarterly cash dividend on The Navigators Group, Inc. Common stock. On July 15, 2016 our Company paid a dividend of $0.09 per share on The Navigators Group, Inc. Common stock to Stockholders of record on June 20, 2016. On September 30, 2016, our Company paid a dividend of $0.09 per share on The Navigators Group, Inc. Common stock to Stockholders of record on August 19, 2016. The declaration and amount of any future dividend will be at the discretion of the Board of Directors, and will depend upon many factors, including financial condition, results of operations, business requirements, regulatory, legal constraints and other factors the Board of Directors deems relevant.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	NOTE 9 On November 3, 2016, our Board of Directors declared a cash dividend on The Navigators Group, Inc. Common stock of $0.09 per share, payable on December 29, 2016 to Stockholders of record on November 18, 2016.

Organization and Summary of S18

Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Organization	Organization We are an international insurance company with a long-standing area of specialization in Marine insurance. We also offer Property and Casualty (“P&C”) insurance business, primarily general liability coverage and umbrella & excess liability coverage to commercial enterprises through our Primary and Excess Casualty divisions. We have also developed niches in Professional Liability insurance, through our Directors & Officers (“D&O”) and Errors & Omissions (“E&O”) divisions. Beginning in 2010, we added reinsurance products through our Global Reinsurance (“GlobalRe”) business. We operate through various wholly-owned subsidiaries, including Navigators Insurance Company (“NIC”), inclusive of its United Kingdom Branch (“U.K. Branch”), and Navigators Specialty Insurance Company (“NSIC”), both of which are U.S. insurance companies, and Navigators Underwriting Agency Ltd. (“NUAL”), a Lloyd’s of London (“Lloyd’s”) underwriting agency that manages Lloyd’s Syndicate 1221 (the “Syndicate”) in the U.K. and is the primary underwriting company of Navigators Holdings (U.K.) Ltd. (“NHUK”), the holding company for our non U.S. domiciled entities. Our Company controls 100% of the Syndicate’s stamp capacity.
Basis of Presentation	Basis of Presentation The accompanying Interim Consolidated Financial Statements are unaudited and reflect all adjustments, which, in the opinion of management, are necessary to fairly present the results of The Navigators Group, Inc. and its subsidiaries for the interim periods presented on the basis of United States generally accepted accounting principles (“GAAP” or “U.S. GAAP”). All significant intercompany transactions and balances have been eliminated in consolidation. The preparation of these Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the Financial Statements and the reported revenues and expenses during the reporting periods. The results of operations for any interim period are not necessarily indicative of results for the full year. The Interim Consolidated Financial Statements should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2015. Certain amounts for the prior period have been reclassified to conform with the current period presentation.
Income Taxes	Income Taxes The interim income tax provision has been computed based on our estimated annual Effective tax rate, which represents our best estimate on a year to date basis for the interim period. As a result, the tax provision for a given quarter equals the difference between the provision recorded cumulatively year to date less the amount recorded cumulatively as of the end of the prior interim period. Our Effective tax rate for the quarter and year to date differs from the federal tax rate of 35% primarily due to tax-exempt investment income and dividends received deduction.
Current and Pending Accounting Pronouncements	Current and Pending Accounting Pronouncements As of January 1, 2016, we adopted the following accounting pronouncements, which did not have a material effect, singly or in the aggregate, on our Consolidated Financial Statements: • Accounting Standards Update 2015-03 – Interest – Imputation of Interest (Subtopic 835-30) – Simplifying the Presentation of Debt Issuance Costs, which is effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to simplify presentation of debt issuance costs. • Accounting Standards Update 2015-05 – Intangibles – Goodwill and Other – Internal Use Software (Subtopic 350-40) Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement, which is effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to provide guidance to customers about whether a cloud computing arrangement includes a software license. • Accounting Standards Update 2015-07 – Fair Value Measurement – (Topic 820) Disclosures for Investments in Certain Entities that Calculate Net Asset Value per Share (or its equivalent) (a consensus of the Emerging Issues Task Force), which is effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to ensure that all investments categorized in the fair value hierarchy are classified using a consistent approach. In 2016, the Financial Accounting Standards Board issued the following new pronouncements that may have an impact on our Company and we are assessing the future impact of these updates on our Consolidated Financial Statements: • Accounting Standards Update 2016-01 – Financial Instruments (Subtopic 825-10) – Recognition and Measurement of Financial Assets and Financial Liabilities, which will be effective for fiscal years beginning after December 15, 2017. The new pronouncement was issued to make targeted improvements to the presentation of financial instruments. • Accounting Standards Update 2016-02 – Leases (Topic 842) – Amends the recognition of a right-to-use asset and lease liability on the statement of financial position of those leases previously classified as operating leases under the previous guidance, which will be effective for fiscal years beginning after December 15, 2015. The new pronouncement was issued to improve transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. • Accounting Standards Update 2016-09 – Compensation – Stock Compensation – (Topic 718) – Improvements to Employee Share-Based Accounting, which will be effective for fiscal years beginning after December 15, 2016. The new pronouncement was issued to simplify employee share-based accounting. • Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326) – amends the measurement of credit losses on financial instruments not accounted for at fair value including loans, debt securities, reinsurance receivables and any other financial assets, which will be effective for the fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. • Accounting Standards Update 2016-15 – Statements of Cash Flows (Topic 230) – Classification of Certain Cash Receipts and Cash Payments amends how certain cash receipts and cash payments are presented in the statement of cash flows to reduce existing diversity in practice. There were no additional 2016 accounting pronouncements that are expected to have an impact on the Consolidated Financial Statements upon adoption.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Financial Data by Segment	Financial data by segment for the three and nine months ended September 30, 2016 and 2015 was as follows: Three Months Ended September 30, 2016 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 161,722 $ 79,761 $ 42,527 $ — $ 284,010 Net losses and LAE (106,320 ) (45,043 ) (21,430 ) — (172,793 ) Commission expenses (18,630 ) (15,348 ) (8,951 ) 318 (42,611 ) Other operating expenses (31,517 ) (20,183 ) (4,437 ) — (56,137 ) Other underwriting income (expense) 240 — 122 (318 ) 44 Underwriting profit (loss) $ 5,495 $ (813 ) $ 7,831 $ — $ 12,513 Net investment income 19,875 19,875 Net realized gains (losses) 1,586 1,586 Interest expense (3,859 ) (3,859 ) Other income (loss) (227 ) (227 ) Income before income taxes $ 5,495 $ (813 ) $ 7,831 $ 17,375 $ 29,888 Income tax (expense) benefit (7,875 ) (7,875 ) Net income (loss) $ 22,013 Losses and LAE ratio 65.7 % 56.5 % 50.4 % 60.8 % Commission expense ratio 11.5 % 19.2 % 21.0 % 15.0 % Other operating expense ratio (2) 19.4 % 25.3 % 10.2 % 19.8 % Combined ratio 96.6 % 101.0 % 81.6 % 95.6 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense). Three Months Ended September 30, 2015 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 142,409 $ 68,533 $ 43,140 $ — $ 254,082 Net losses and LAE (85,140 ) (39,182 ) (22,224 ) — (146,546 ) Commission expenses (15,157 ) (12,780 ) (7,705 ) 1,389 (34,253 ) Other operating expenses (32,948 ) (19,937 ) (3,714 ) — (56,599 ) Other underwriting income (expense) 1,013 — 395 (1,389 ) 19 Underwriting profit (loss) $ 10,177 $ (3,366 ) $ 9,892 $ — $ 16,703 Net investment income 17,371 17,371 Net realized gains (losses) (757 ) (757 ) Interest expense (3,856 ) (3,856 ) Other income (loss) (2,537 ) (2,537 ) Income before income taxes $ 10,177 $ (3,366 ) $ 9,892 $ 10,221 $ 26,924 Income tax (expense) benefit (8,723 ) (8,723 ) Net income (loss) $ 18,201 Losses and LAE ratio 59.8 % 57.2 % 51.5 % 57.7 % Commission expense ratio 10.6 % 18.6 % 17.9 % 13.5 % Other operating expense ratio (2) 22.5 % 29.1 % 7.7 % 22.2 % Combined ratio 92.9 % 104.9 % 77.1 % 93.4 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense). Nine Months Ended September 30, 2016 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 462,446 $ 235,602 $ 118,312 $ — $ 816,360 Net losses and LAE (291,260 ) (133,519 ) (68,176 ) — (492,955 ) Commission expenses (50,379 ) (47,524 ) (24,188 ) 1,200 (120,891 ) Other operating expenses (96,848 ) (64,997 ) (14,175 ) — (176,020 ) Other underwriting income (expense) 943 — 374 (1,200 ) 117 Underwriting profit (loss) $ 24,902 $ (10,438 ) $ 12,147 $ — $ 26,611 Net investment income 59,344 59,344 Net realized gains (losses) 4,993 4,993 Interest expense (11,575 ) (11,575 ) Other income (loss) 6,679 6,679 Income (loss) before income taxes $ 24,902 $ (10,438 ) $ 12,147 $ 59,441 $ 86,052 Income tax (expense) benefit (24,917 ) (24,917 ) Net income (loss) $ 61,135 Losses and LAE ratio 63.0 % 56.7 % 57.6 % 60.4 % Commission expense ratio 10.9 % 20.2 % 20.4 % 14.8 % Other operating expense ratio (2) 20.7 % 27.5 % 11.7 % 21.5 % Combined ratio 94.6 % 104.4 % 89.7 % 96.7 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense). Nine Months Ended September 30, 2015 U.S. Int'l amounts in thousands Insurance Insurance GlobalRe Corporate (1) Total Net earned premiums $ 410,804 $ 197,244 $ 124,494 $ — $ 732,542 Net losses and LAE (247,094 ) (101,236 ) (70,387 ) — (418,717 ) Commission expenses (41,777 ) (35,491 ) (23,042 ) 1,672 (98,638 ) Other operating expenses (98,010 ) (54,312 ) (11,975 ) — (164,297 ) Other underwriting income (expense) 1,330 — 441 (1,672 ) 99 Underwriting profit (loss) $ 25,253 $ 6,205 $ 19,531 $ — $ 50,989 Net investment income 50,219 50,219 Net realized gains (losses) 8,755 8,755 Interest expense (11,567 ) (11,567 ) Other income (loss) (4,737 ) (4,737 ) Income (loss) before income taxes $ 25,253 $ 6,205 $ 19,531 $ 42,670 $ 93,659 Income tax (expense) benefit (30,345 ) (30,345 ) Net income (loss) $ 63,314 Losses and LAE ratio 60.1 % 51.3 % 56.5 % 57.2 % Commission expense ratio 10.2 % 18.0 % 18.5 % 13.5 % Other operating expense ratio (2) 23.6 % 27.6 % 9.3 % 22.3 % Combined ratio 93.9 % 96.9 % 84.3 % 93.0 % (1) - Includes Corporate segment intercompany eliminations. (2) - Includes Other operating expenses and Other underwriting income (expense).
Additional Financial Data by Segment	Revenue by operating segment for the three and nine months ended September 30, 2016 and 2015 was as follows: Three Months Ended September 30, 2016 Three Months Ended September 30, 2015 % Change amounts in thousands Gross written premiums Ceded written premiums Net premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums U.S. Insurance Marine $ 40,271 $ (17,636 ) $ 22,635 $ 25,465 $ 35,529 $ (13,865 ) $ 21,664 $ 24,292 13.3 % 27.2 % 4.5 % 4.8 % P&C 161,600 (36,011 ) 125,589 115,971 154,009 (34,902 ) 119,107 104,473 4.9 % 3.2 % 5.4 % 11.0 % Professional 32,776 (7,712 ) 25,064 20,286 29,245 (14,986 ) 14,259 13,644 12.1 % (48.5 %) 75.8 % 48.7 % Total $ 234,647 $ (61,359 ) $ 173,288 $ 161,722 $ 218,783 $ (63,753 ) $ 155,030 $ 142,409 7.3 % (3.8 %) 11.8 % 13.6 % Int'l Insurance Marine $ 38,453 $ (12,631 ) $ 25,822 $ 34,794 $ 41,002 $ (10,985 ) $ 30,017 $ 36,792 (6.2 %) 15.0 % (14.0 %) (5.4 %) P&C 38,077 (15,331 ) 22,746 25,584 37,449 (20,034 ) 17,415 16,879 1.7 % (23.5 %) 30.6 % 51.6 % Professional Liability 27,954 (7,232 ) 20,722 19,383 20,337 (6,785 ) 13,552 14,862 37.5 % 6.6 % 52.9 % 30.4 % Total $ 104,484 $ (35,194 ) $ 69,290 $ 79,761 $ 98,788 $ (37,804 ) $ 60,984 $ 68,533 5.8 % (6.9 %) 13.6 % 16.4 % GlobalRe $ 35,799 $ (1,376 ) $ 34,423 $ 42,527 $ 36,491 $ (566 ) $ 35,925 $ 43,140 (1.9 %) 143.2 % (4.2 %) (1.4 %) Total $ 374,930 $ (97,929 ) $ 277,001 $ 284,010 $ 354,062 $ (102,123 ) $ 251,939 $ 254,082 5.9 % (4.1 %) 9.9 % 11.8 % Nine Months Ended September 30, 2016 Nine Months Ended September 30, 2015 % Change amounts in thousands Gross written premiums Ceded written premiums Net premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums Gross written premiums Ceded written premiums Net written premiums Net earned premiums U.S. Insurance Marine $ 129,621 $ (53,823 ) $ 75,798 $ 73,636 $ 118,167 $ (45,177 ) $ 72,990 $ 74,193 9.7 % 19.1 % 3.8 % (0.7 %) P&C 471,532 (103,286 ) 368,246 335,342 458,371 (123,765 ) 334,606 291,648 2.9 % (16.5 %) 10.1 % 15.0 % Professional 88,065 (21,365 ) 66,700 53,468 81,559 (42,423 ) 39,136 44,963 8.0 % (49.6 %) 70.4 % 18.9 % Total $ 689,218 $ (178,474 ) $ 510,744 $ 462,446 $ 658,097 $ (211,365 ) $ 446,732 $ 410,804 4.7 % (15.6 %) 14.3 % 12.6 % Int'l Insurance Marine $ 151,548 $ (33,274 ) $ 118,274 $ 109,746 $ 149,844 $ (30,933 ) $ 118,911 $ 114,716 1.1 % 7.6 % (0.5 %) (4.3 %) P&C 145,125 (57,025 ) 88,100 70,608 112,014 (60,676 ) 51,338 43,112 29.6 % (6.0 %) 71.6 % 63.8 % Professional 87,694 (21,776 ) 65,918 55,248 68,147 (22,072 ) 46,075 39,416 28.7 % (1.3 %) 43.1 % 40.2 % Total $ 384,367 $ (112,075 ) $ 272,292 $ 235,602 $ 330,005 $ (113,681 ) $ 216,324 $ 197,244 16.5 % (1.4 %) 25.9 % 19.4 % GlobalRe $ 127,787 $ (7,467 ) $ 120,320 $ 118,312 $ 141,891 $ (5,806 ) $ 136,085 $ 124,494 (9.9 %) 28.6 % (11.6 %) (5.0 %) Total $ 1,201,372 $ (298,016 ) $ 903,356 $ 816,360 $ 1,129,993 $ (330,852 ) $ 799,141 $ 732,542 6.3 % (9.9 %) 13.0 % 11.4 %

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Investments Including Other-Than-Temporarily Impaired Securities Recognized within Accumulated Other Comprehensive Income	The following tables set forth our Company’s investments as of September 30, 2016 and December 31, 2015 and include Other-than-temporary-impairment (“OTTI”) securities recognized within Accumulated other comprehensive income (“AOCI”): September 30, 2016 Gross Gross Cost or Fair Unrealized Unrealized Amortized amounts in thousands Value Gains (Losses) Cost Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 262,030 $ 3,691 $ (3,981 ) $ 262,320 States, municipalities and political subdivisions 580,324 29,288 (769 ) 551,805 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 526,069 11,778 (105 ) 514,396 Residential mortgage obligations 27,055 455 (97 ) 26,697 Asset-backed securities 288,636 1,503 (458 ) 287,591 Commercial mortgage-backed securities 165,405 6,392 (423 ) 159,436 Subtotal $ 1,007,165 $ 20,128 $ (1,083 ) $ 988,120 Corporate bonds 810,898 23,447 (1,354 ) 788,805 Total fixed maturities $ 2,660,417 $ 76,554 $ (7,187 ) $ 2,591,050 Equity securities 342,677 38,538 (1,767 ) 305,906 Other invested assets 2,021 — — 2,021 Short-term investments 134,273 — — 134,273 Total investments $ 3,139,388 $ 115,092 $ (8,954 ) $ 3,033,250 December 31, 2015 Gross Gross Cost or Fair Unrealized Unrealized Amortized amounts in thousands Value Gains (Losses) Cost Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 252,882 $ 2,273 $ (9,214 ) $ 259,823 States, municipalities and political subdivisions 576,859 21,233 (781 ) 556,407 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 379,269 5,573 (2,082 ) 375,778 Residential mortgage obligations 30,465 694 (82 ) 29,853 Asset-backed securities 225,012 85 (1,624 ) 226,551 Commercial mortgage-backed securities 189,713 3,119 (1,864 ) 188,458 Subtotal $ 824,459 $ 9,471 $ (5,652 ) $ 820,640 Corporate bonds 760,010 7,373 (10,738 ) 763,375 Total fixed maturities $ 2,414,210 $ 40,350 $ (26,385 ) $ 2,400,245 Equity securities 305,271 26,341 (3,013 ) 281,943 Short-term investments 217,745 2 — 217,743 Total investments $ 2,937,226 $ 66,693 $ (29,398 ) $ 2,899,931
Scheduled Maturity Dates for Fixed Maturity Securities by Number of Years Until Maturity	The contractual maturity dates for Fixed maturities categorized by the number of years until maturity as of September 30, 2016 are shown in the following table: September 30, 2016 Fair Amortized amounts in thousands Value Cost Due in one year or less $ 81,849 $ 83,551 Due after one year through five years 810,165 799,159 Due after five years through ten years 296,471 281,368 Due after ten years 464,767 438,852 Mortgage-backed and asset-backed securities 1,007,165 988,120 Total $ 2,660,417 $ 2,591,050
Summary of Aggregate Fair Value and Gross Unrealized Loss by Length of Time Securities had Continuously been in Gross Unrealized Loss Position	The following tables summarize all securities in a gross unrealized loss position as of September 30, 2016 and December 31, 2015, showing the aggregate fair value and gross unrealized loss by the length of time those securities have continuously been in a gross unrealized loss position: September 30, 2016 Less than 12 months Greater than 12 months Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized amounts in thousands Value (Losses) Value (Losses) Value (Losses) Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 91,676 $ (969 ) $ 19,897 $ (3,012 ) $ 111,573 $ (3,981 ) States, municipalities and political subdivisions 49,881 (593 ) 9,932 (176 ) 59,813 (769 ) Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 52,754 (17 ) 13,547 (88 ) 66,301 (105 ) Residential mortgage obligations 1,317 (16 ) 1,631 (81 ) 2,948 (97 ) Asset-backed securities 22,422 (158 ) 61,499 (300 ) 83,921 (458 ) Commercial mortgage-backed securities 20,864 (38 ) 8,854 (385 ) 29,718 (423 ) Subtotal $ 97,357 $ (229 ) $ 85,531 $ (854 ) $ 182,888 $ (1,083 ) Corporate bonds 120,114 (622 ) 23,053 (732 ) 143,167 (1,354 ) Total fixed maturities $ 359,028 $ (2,413 ) $ 138,413 $ (4,774 ) $ 497,441 $ (7,187 ) Equity securities 38,050 (1,490 ) 4,723 (277 ) 42,773 (1,767 ) Total fixed maturities and equity securities $ 397,078 $ (3,903 ) $ 143,136 $ (5,051 ) $ 540,214 $ (8,954 ) December 31, 2015 Less than 12 months Greater than 12 months Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized amounts in thousands Value (Losses) Value (Losses) Value (Losses) Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 142,233 $ (3,032 ) $ 22,230 $ (6,182 ) $ 164,463 $ (9,214 ) States, municipalities and political subdivisions 50,577 (549 ) 4,808 (232 ) 55,385 (781 ) Mortgage-backed and asset-backed securities: Agency mortgage-backed securities 164,817 (1,315 ) 29,862 (767 ) 194,679 (2,082 ) Residential mortgage obligations 3,910 (5 ) 1,684 (77 ) 5,594 (82 ) Asset-backed securities 112,479 (663 ) 81,477 (961 ) 193,956 (1,624 ) Commercial mortgage-backed securities 83,024 (1,826 ) 3,065 (38 ) 86,089 (1,864 ) Subtotal $ 364,230 $ (3,809 ) $ 116,088 $ (1,843 ) $ 480,318 $ (5,652 ) Corporate bonds 395,399 (10,114 ) 13,849 (624 ) 409,248 (10,738 ) Total fixed maturities $ 952,439 $ (17,504 ) $ 156,975 $ (8,881 ) $ 1,109,414 $ (26,385 ) Equity securities 58,531 (3,013 ) — — 58,531 (3,013 ) Total fixed maturities and equity securities $ 1,010,970 $ (20,517 ) $ 156,975 $ (8,881 ) $ 1,167,945 $ (29,398 )
Summary of Cumulative Amounts Related to Credit Loss Portion of Other-Than-Temporary Impairment Losses on Debt Securities	The following table summarizes the cumulative amounts related to our Company’s credit loss portion of the OTTI losses on Fixed maturities for the three and nine months ended September 30, 2016 and 2015: Three Months Ended September 30, Nine Months Ended September 30, amounts in thousands 2016 2015 2016 2015 Beginning balance $ 2,511 $ 2,361 $ 2,361 $ 2,361 Additions for credit loss impairments recognized in the current period on securities not previously impaired — — 150 — Additions for credit loss impairments recognized in the current period on securities previously impaired — — — — Reductions for credit loss impairments previously recognized on securities sold during the period (150 ) — (150 ) — Ending balance $ 2,361 $ 2,361 $ 2,361 $ 2,361
Net Investment Income	Our Company’s Net investment income was derived from the following sources: Three Months Ended September 30, Nine Months Ended September 30, amounts in thousands 2016 2015 2016 2015 Fixed maturities $ 17,124 $ 15,353 $ 50,781 $ 45,660 Equity securities 3,540 2,543 10,418 6,383 Short-term investments 70 272 568 604 Total investment income $ 20,734 $ 18,168 $ 61,767 $ 52,647 Investment expenses (859 ) (797 ) (2,423 ) (2,428 ) Net investment income $ 19,875 $ 17,371 $ 59,344 $ 50,219
Realized Gains and Losses, Excluding Net Other-Than-Temporary Impairment Losses Recognized in Earnings	Realized gains and losses, excluding net OTTI losses recognized in earnings, for the periods indicated, were as follows: Three Months Ended September 30, Nine Months Ended September 30, amounts in thousands 2016 2015 2016 2015 Fixed maturities: Gains $ 1,356 $ 484 $ 5,200 $ 2,889 Losses (1,221 ) (667 ) (3,086 ) (2,757 ) Fixed maturities, net $ 135 $ (183 ) $ 2,114 $ 132 Short-term: Gains $ 128 $ 9 $ 803 $ 109 Losses (107 ) (120 ) (250 ) (273 ) Short-term, net $ 21 $ (111 ) $ 553 $ (164 ) Equity securities: Gains $ 1,443 $ 1,107 $ 3,123 $ 12,185 Losses (13 ) (295 ) (647 ) (1,700 ) Equity securities, net $ 1,430 $ 812 $ 2,476 $ 10,485 Net realized gains (losses) $ 1,586 $ 518 $ 5,143 $ 10,453

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fixed Maturities and Equity Securities by Asset Class that are Measured at Fair Value	The following tables present, for each of the fair value hierarchy levels as defined by the accounting guidance for fair value measurements and described above, our Company’s Fixed maturities and Equity securities by asset class that are measured at fair value on a recurring basis, as well as the fair value of the 5.75% Senior notes due October 15, 2023 (the “Senior notes”) carried at amortized cost as of September 30, 2016 and December 31, 2015: September 30, 2016 amounts in thousands Level 1 Level 2 Level 3 Fair Value based on net asset value Total Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 55,159 $ 206,871 $ — $ — $ 262,030 States, municipalities and political subdivisions — 580,324 — — 580,324 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities — 526,069 — — 526,069 Residential mortgage obligations — 27,055 — — 27,055 Asset-backed securities — 288,636 — — 288,636 Commercial mortgage-backed securities — 165,405 — — 165,405 Subtotal $ — $ 1,007,165 $ — $ — $ 1,007,165 Corporate bonds — 810,898 — — 810,898 Total fixed maturities $ 55,159 $ 2,605,258 $ — $ — $ 2,660,417 Equity securities 158,963 183,714 — 342,677 Other invested assets — — — 2,021 2,021 Short-term investments 134,273 — — — 134,273 Total assets measured at fair value $ 348,395 $ 2,788,972 $ — $ 2,021 $ 3,139,388 Senior notes $ — $ 294,080 $ — $ — $ 294,080 Total liabilities measured at fair value $ — $ 294,080 $ — $ — $ 294,080 December 31, 2015 amounts in thousands Level 1 Level 2 Level 3 Total Fixed maturities: U.S. Treasury bonds, agency bonds and foreign government bonds $ 67,394 $ 185,488 $ — $ 252,882 States, municipalities and political subdivisions — 576,859 — 576,859 Mortgage-backed and asset-backed securities: Agency mortgage-backed securities — 379,269 — 379,269 Residential mortgage obligations — 30,465 — 30,465 Asset-backed securities — 225,012 — 225,012 Commercial mortgage-backed securities — 189,713 — 189,713 Subtotal $ — $ 824,459 $ — $ 824,459 Corporate bonds — 760,010 — 760,010 Total fixed maturities $ 67,394 $ 2,346,816 $ — $ 2,414,210 Equity securities 126,455 178,816 — 305,271 Short-term investments 217,745 — — 217,745 Total assets measured at fair value $ 411,594 $ 2,525,632 $ — $ 2,937,226 Senior notes $ — $ 282,486 $ — $ 282,486 Total liabilities measured at fair value $ — $ 282,486 $ — $ 282,486

Organization and Summary of S22

Organization and Summary of Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016
Organization And Summary Of Significant Accounting Policies [Line Items]
Effective Tax Rate	35.00%
Syndicate 1,221
Organization And Summary Of Significant Accounting Policies [Line Items]
Percentage control of stamp capacity	100.00%

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016Segment
Segment Reporting [Abstract]
Number of underwriting Segments	3
Number of Operating Segments	3

Financial Data by Segment (Deta

Financial Data by Segment (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Net earned premiums		$ 284,010	$ 254,082	$ 816,360	$ 732,542
Net losses and LAE		(172,793)	(146,546)	(492,955)	(418,717)
Commission expenses		(42,611)	(34,253)	(120,891)	(98,638)
Other operating expenses		(56,137)	(56,599)	(176,020)	(164,297)
Other underwriting income (expense)		44	19	117	99
Underwriting profit (loss)		12,513	16,703	26,611	50,989
Net investment income		19,875	17,371	59,344	50,219
Net realized gains (losses)		1,586	(757)	4,993	8,755
Interest expense		(3,859)	(3,856)	(11,575)	(11,567)
Other income (loss)		(227)	(2,537)	6,679	(4,737)
Income before income taxes		29,888	26,924	86,052	93,659
Income tax (expense) benefit		(7,875)	(8,723)	(24,917)	(30,345)
Net income		$ 22,013	$ 18,201	$ 61,135	$ 63,314
Losses and LAE ratio		60.80%	57.70%	60.40%	57.20%
Commission expense ratio		15.00%	13.50%	14.80%	13.50%
Other operating expense ratio	[1]	19.80%	22.20%	21.50%	22.30%
Combined ratio		95.60%	93.40%	96.70%	93.00%
U.S.Insurance
Segment Reporting Information [Line Items]
Net earned premiums		$ 161,722	$ 142,409	$ 462,446	$ 410,804
Net losses and LAE		(106,320)	(85,140)	(291,260)	(247,094)
Commission expenses		(18,630)	(15,157)	(50,379)	(41,777)
Other operating expenses		(31,517)	(32,948)	(96,848)	(98,010)
Other underwriting income (expense)		240	1,013	943	1,330
Underwriting profit (loss)		5,495	10,177	24,902	25,253
Income before income taxes		$ 5,495	$ 10,177	$ 24,902	$ 25,253
Losses and LAE ratio		65.70%	59.80%	63.00%	60.10%
Commission expense ratio		11.50%	10.60%	10.90%	10.20%
Other operating expense ratio	[1]	19.40%	22.50%	20.70%	23.60%
Combined ratio		96.60%	92.90%	94.60%	93.90%
International Insurance
Segment Reporting Information [Line Items]
Net earned premiums		$ 79,761	$ 68,533	$ 235,602	$ 197,244
Net losses and LAE		(45,043)	(39,182)	(133,519)	(101,236)
Commission expenses		(15,348)	(12,780)	(47,524)	(35,491)
Other operating expenses		(20,183)	(19,937)	(64,997)	(54,312)
Underwriting profit (loss)		(813)	(3,366)	(10,438)	6,205
Income before income taxes		$ (813)	$ (3,366)	$ (10,438)	$ 6,205
Losses and LAE ratio		56.50%	57.20%	56.70%	51.30%
Commission expense ratio		19.20%	18.60%	20.20%	18.00%
Other operating expense ratio	[1]	25.30%	29.10%	27.50%	27.60%
Combined ratio		101.00%	104.90%	104.40%	96.90%
Global Reinsurance
Segment Reporting Information [Line Items]
Net earned premiums		$ 42,527	$ 43,140	$ 118,312	$ 124,494
Net losses and LAE		(21,430)	(22,224)	(68,176)	(70,387)
Commission expenses		(8,951)	(7,705)	(24,188)	(23,042)
Other operating expenses		(4,437)	(3,714)	(14,175)	(11,975)
Other underwriting income (expense)		122	395	374	441
Underwriting profit (loss)		7,831	9,892	12,147	19,531
Income before income taxes		$ 7,831	$ 9,892	$ 12,147	$ 19,531
Losses and LAE ratio		50.40%	51.50%	57.60%	56.50%
Commission expense ratio		21.00%	17.90%	20.40%	18.50%
Other operating expense ratio	[1]	10.20%	7.70%	11.70%	9.30%
Combined ratio		81.60%	77.10%	89.70%	84.30%
Corporate
Segment Reporting Information [Line Items]
Commission expenses	[2]	$ 318	$ 1,389	$ 1,200	$ 1,672
Other underwriting income (expense)	[2]	(318)	(1,389)	(1,200)	(1,672)
Net investment income	[2]	19,875	17,371	59,344	50,219
Net realized gains (losses)	[2]	1,586	(757)	4,993	8,755
Interest expense	[2]	(3,859)	(3,856)	(11,575)	(11,567)
Other income (loss)	[2]	(227)	(2,537)	6,679	(4,737)
Income before income taxes	[2]	17,375	10,221	59,441	42,670
Income tax (expense) benefit	[2]	$ (7,875)	$ (8,723)	$ (24,917)	$ (30,345)
[1]	Includes Other operating expenses and Other underwriting income (expense).
[2]	Includes Corporate segment intercompany eliminations.

Additional Financial Data by Se

Additional Financial Data by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Gross written premiums	$ 374,930	$ 354,062	$ 1,201,372	$ 1,129,993
Ceded written premiums	(97,929)	(102,123)	(298,016)	(330,852)
Net written premiums	277,001	251,939	903,356	799,141
Net earned premiums	$ 284,010	254,082	$ 816,360	732,542
% Change Gross written premiums	5.90%		6.30%
% Change Ceded written premiums	(4.10%)		(9.90%)
% Change Net written premiums	9.90%		13.00%
% Change Net earned premiums	11.80%		11.40%
U.S.Insurance
Segment Reporting Information [Line Items]
Gross written premiums	$ 234,647	218,783	$ 689,218	658,097
Ceded written premiums	(61,359)	(63,753)	(178,474)	(211,365)
Net written premiums	173,288	155,030	510,744	446,732
Net earned premiums	$ 161,722	142,409	$ 462,446	410,804
% Change Gross written premiums	7.30%		4.70%
% Change Ceded written premiums	(3.80%)		(15.60%)
% Change Net written premiums	11.80%		14.30%
% Change Net earned premiums	13.60%		12.60%
U.S.Insurance | Marine
Segment Reporting Information [Line Items]
Gross written premiums	$ 40,271	35,529	$ 129,621	118,167
Ceded written premiums	(17,636)	(13,865)	(53,823)	(45,177)
Net written premiums	22,635	21,664	75,798	72,990
Net earned premiums	$ 25,465	24,292	$ 73,636	74,193
% Change Gross written premiums	13.30%		9.70%
% Change Ceded written premiums	27.20%		19.10%
% Change Net written premiums	4.50%		3.80%
% Change Net earned premiums	4.80%		(0.70%)
U.S.Insurance | Property Casualty
Segment Reporting Information [Line Items]
Gross written premiums	$ 161,600	154,009	$ 471,532	458,371
Ceded written premiums	(36,011)	(34,902)	(103,286)	(123,765)
Net written premiums	125,589	119,107	368,246	334,606
Net earned premiums	$ 115,971	104,473	$ 335,342	291,648
% Change Gross written premiums	4.90%		2.90%
% Change Ceded written premiums	3.20%		(16.50%)
% Change Net written premiums	5.40%		10.10%
% Change Net earned premiums	11.00%		15.00%
U.S.Insurance | Professional Liability
Segment Reporting Information [Line Items]
Gross written premiums	$ 32,776	29,245	$ 88,065	81,559
Ceded written premiums	(7,712)	(14,986)	(21,365)	(42,423)
Net written premiums	25,064	14,259	66,700	39,136
Net earned premiums	$ 20,286	13,644	$ 53,468	44,963
% Change Gross written premiums	12.10%		8.00%
% Change Ceded written premiums	(48.50%)		(49.60%)
% Change Net written premiums	75.80%		70.40%
% Change Net earned premiums	48.70%		18.90%
International Insurance
Segment Reporting Information [Line Items]
Gross written premiums	$ 104,484	98,788	$ 384,367	330,005
Ceded written premiums	(35,194)	(37,804)	(112,075)	(113,681)
Net written premiums	69,290	60,984	272,292	216,324
Net earned premiums	$ 79,761	68,533	$ 235,602	197,244
% Change Gross written premiums	5.80%		16.50%
% Change Ceded written premiums	(6.90%)		(1.40%)
% Change Net written premiums	13.60%		25.90%
% Change Net earned premiums	16.40%		19.40%
International Insurance | Marine
Segment Reporting Information [Line Items]
Gross written premiums	$ 38,453	41,002	$ 151,548	149,844
Ceded written premiums	(12,631)	(10,985)	(33,274)	(30,933)
Net written premiums	25,822	30,017	118,274	118,911
Net earned premiums	$ 34,794	36,792	$ 109,746	114,716
% Change Gross written premiums	(6.20%)		1.10%
% Change Ceded written premiums	15.00%		7.60%
% Change Net written premiums	(14.00%)		(0.50%)
% Change Net earned premiums	(5.40%)		(4.30%)
International Insurance | Property Casualty
Segment Reporting Information [Line Items]
Gross written premiums	$ 38,077	37,449	$ 145,125	112,014
Ceded written premiums	(15,331)	(20,034)	(57,025)	(60,676)
Net written premiums	22,746	17,415	88,100	51,338
Net earned premiums	$ 25,584	16,879	$ 70,608	43,112
% Change Gross written premiums	1.70%		29.60%
% Change Ceded written premiums	(23.50%)		(6.00%)
% Change Net written premiums	30.60%		71.60%
% Change Net earned premiums	51.60%		63.80%
International Insurance | Professional Liability
Segment Reporting Information [Line Items]
Gross written premiums	$ 27,954	20,337	$ 87,694	68,147
Ceded written premiums	(7,232)	(6,785)	(21,776)	(22,072)
Net written premiums	20,722	13,552	65,918	46,075
Net earned premiums	$ 19,383	14,862	$ 55,248	39,416
% Change Gross written premiums	37.50%		28.70%
% Change Ceded written premiums	6.60%		(1.30%)
% Change Net written premiums	52.90%		43.10%
% Change Net earned premiums	30.40%		40.20%
Global Reinsurance
Segment Reporting Information [Line Items]
Gross written premiums	$ 35,799	36,491	$ 127,787	141,891
Ceded written premiums	(1,376)	(566)	(7,467)	(5,806)
Net written premiums	34,423	35,925	120,320	136,085
Net earned premiums	$ 42,527	$ 43,140	$ 118,312	$ 124,494
% Change Gross written premiums	(1.90%)		(9.90%)
% Change Ceded written premiums	143.20%		28.60%
% Change Net written premiums	(4.20%)		(11.60%)
% Change Net earned premiums	(1.40%)		(5.00%)

Investments Including Other-Tha

Investments Including Other-Than-Temporarily Impaired Securities Recognized within Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Gain (Loss) on Investments [Line Items]
Total investments	$ 3,139,388	$ 2,937,226
Gross Unrealized Gains	115,092	66,693
Gross Unrealized Losses	(8,954)	(29,398)
Amortized Cost	3,033,250	2,899,931
Fixed maturities
Gain (Loss) on Investments [Line Items]
Total investments	2,660,417	2,414,210
Gross Unrealized Gains	76,554	40,350
Gross Unrealized Losses	(7,187)	(26,385)
Amortized Cost	2,591,050	2,400,245
Fixed maturities | U.S. Treasury bonds, agency bonds, and foreign
Gain (Loss) on Investments [Line Items]
Total investments	262,030	252,882
Gross Unrealized Gains	3,691	2,273
Gross Unrealized Losses	(3,981)	(9,214)
Amortized Cost	262,320	259,823
Fixed maturities | States, municipalities and political subdivisions
Gain (Loss) on Investments [Line Items]
Total investments	580,324	576,859
Gross Unrealized Gains	29,288	21,233
Gross Unrealized Losses	(769)	(781)
Amortized Cost	551,805	556,407
Fixed maturities | Agency mortgage-backed securities
Gain (Loss) on Investments [Line Items]
Total investments	526,069	379,269
Gross Unrealized Gains	11,778	5,573
Gross Unrealized Losses	(105)	(2,082)
Amortized Cost	514,396	375,778
Fixed maturities | Residential Mortgage Backed Securities
Gain (Loss) on Investments [Line Items]
Total investments	27,055	30,465
Gross Unrealized Gains	455	694
Gross Unrealized Losses	(97)	(82)
Amortized Cost	26,697	29,853
Fixed maturities | Asset-backed securities
Gain (Loss) on Investments [Line Items]
Total investments	288,636	225,012
Gross Unrealized Gains	1,503	85
Gross Unrealized Losses	(458)	(1,624)
Amortized Cost	287,591	226,551
Fixed maturities | Commercial mortgage-backed securities
Gain (Loss) on Investments [Line Items]
Total investments	165,405	189,713
Gross Unrealized Gains	6,392	3,119
Gross Unrealized Losses	(423)	(1,864)
Amortized Cost	159,436	188,458
Fixed maturities | Mortgage-backed and asset-backed securities
Gain (Loss) on Investments [Line Items]
Total investments	1,007,165	824,459
Gross Unrealized Gains	20,128	9,471
Gross Unrealized Losses	(1,083)	(5,652)
Amortized Cost	988,120	820,640
Fixed maturities | Corporate bonds
Gain (Loss) on Investments [Line Items]
Total investments	810,898	760,010
Gross Unrealized Gains	23,447	7,373
Gross Unrealized Losses	(1,354)	(10,738)
Amortized Cost	788,805	763,375
Equity Securities
Gain (Loss) on Investments [Line Items]
Total investments	342,677	305,271
Gross Unrealized Gains	38,538	26,341
Gross Unrealized Losses	(1,767)	(3,013)
Amortized Cost	305,906	281,943
Short-term investments
Gain (Loss) on Investments [Line Items]
Total investments	134,273	217,745
Gross Unrealized Gains		2
Amortized Cost	134,273	$ 217,743
Other Invested Assets
Gain (Loss) on Investments [Line Items]
Total investments	2,021
Amortized Cost	$ 2,021

Investments - Additional Inform

Investments - Additional Information (Detail) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)Security	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)Security
Schedule of Investments [Line Items]
Non-credit OTTI on fixed maturities in a net unrealized net gain position		$ 400		$ 500
Gross Unrealized Loss		8,954		$ 29,398
OTTI losses	$ 1,275	$ 150	$ 1,698
Equity Securities
Schedule of Investments [Line Items]
Number of securities in unrealized loss position | Security		42		57
Gross Unrealized Loss		$ 1,767		$ 3,013
Fixed maturities
Schedule of Investments [Line Items]
Number of securities in unrealized loss position | Security		177		368
Gross Unrealized Loss		$ 7,187		$ 26,385
OTTI losses		200
Equity Portfolio
Schedule of Investments [Line Items]
OTTI losses	$ 1,300		$ 1,700
Non-government-backed securities
Schedule of Investments [Line Items]
Gross Unrealized Loss		$ 400		$ 2,600
Non-government-backed securities | Maximum
Schedule of Investments [Line Items]
Percentage of investment		5.00%		5.00%
Mortgage-backed and asset-backed securities
Schedule of Investments [Line Items]
Securities, effective maturities		4 years 1 month 6 days
Mortgage-backed and asset-backed securities | Fixed maturities
Schedule of Investments [Line Items]
Gross Unrealized Loss		$ 1,083		$ 5,652

Scheduled Maturity Dates for Fi

Scheduled Maturity Dates for Fixed Maturity Securities by Number of Years Until Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value
Due in one year or less	$ 81,849
Due after one year through five years	810,165
Due after five years through ten years	296,471
Due after ten years	464,767
Mortgage-backed and asset-backed securities	1,007,165
Total	2,660,417	$ 2,414,210
Amortized Cost
Due in one year or less	83,551
Due after one year through five years	799,159
Due after five years through ten years	281,368
Due after ten years	438,852
Mortgage-backed and asset-backed securities	988,120
Total	$ 2,591,050	$ 2,400,245

Summary of Aggregate Fair Value

Summary of Aggregate Fair Value and Gross Unrealized Loss by Length of Time Securities had Continuously been in Gross Unrealized Loss Position as Well as Number of Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	$ 397,078	$ 1,010,970
Less than 12 months Gross Unrealized Losses	(3,903)	(20,517)
Greater than 12 months Fair Value	143,136	156,975
Greater than 12 months Gross Unrealized Losses	(5,051)	(8,881)
Fair Value	540,214	1,167,945
Gross Unrealized Losses	(8,954)	(29,398)
Fixed maturities
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	359,028	952,439
Less than 12 months Gross Unrealized Losses	(2,413)	(17,504)
Greater than 12 months Fair Value	138,413	156,975
Greater than 12 months Gross Unrealized Losses	(4,774)	(8,881)
Fair Value	497,441	1,109,414
Gross Unrealized Losses	(7,187)	(26,385)
Fixed maturities | U.S. Treasury bonds, agency bonds, and foreign
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	91,676	142,233
Less than 12 months Gross Unrealized Losses	(969)	(3,032)
Greater than 12 months Fair Value	19,897	22,230
Greater than 12 months Gross Unrealized Losses	(3,012)	(6,182)
Fair Value	111,573	164,463
Gross Unrealized Losses	(3,981)	(9,214)
Fixed maturities | States, municipalities and political subdivisions
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	49,881	50,577
Less than 12 months Gross Unrealized Losses	(593)	(549)
Greater than 12 months Fair Value	9,932	4,808
Greater than 12 months Gross Unrealized Losses	(176)	(232)
Fair Value	59,813	55,385
Gross Unrealized Losses	(769)	(781)
Fixed maturities | Agency mortgage-backed securities
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	52,754	164,817
Less than 12 months Gross Unrealized Losses	(17)	(1,315)
Greater than 12 months Fair Value	13,547	29,862
Greater than 12 months Gross Unrealized Losses	(88)	(767)
Fair Value	66,301	194,679
Gross Unrealized Losses	(105)	(2,082)
Fixed maturities | Residential Mortgage Backed Securities
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	1,317	3,910
Less than 12 months Gross Unrealized Losses	(16)	(5)
Greater than 12 months Fair Value	1,631	1,684
Greater than 12 months Gross Unrealized Losses	(81)	(77)
Fair Value	2,948	5,594
Gross Unrealized Losses	(97)	(82)
Fixed maturities | Asset-backed securities
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	22,422	112,479
Less than 12 months Gross Unrealized Losses	(158)	(663)
Greater than 12 months Fair Value	61,499	81,477
Greater than 12 months Gross Unrealized Losses	(300)	(961)
Fair Value	83,921	193,956
Gross Unrealized Losses	(458)	(1,624)
Fixed maturities | Commercial mortgage-backed securities
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	20,864	83,024
Less than 12 months Gross Unrealized Losses	(38)	(1,826)
Greater than 12 months Fair Value	8,854	3,065
Greater than 12 months Gross Unrealized Losses	(385)	(38)
Fair Value	29,718	86,089
Gross Unrealized Losses	(423)	(1,864)
Fixed maturities | Mortgage-backed and asset-backed securities
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	97,357	364,230
Less than 12 months Gross Unrealized Losses	(229)	(3,809)
Greater than 12 months Fair Value	85,531	116,088
Greater than 12 months Gross Unrealized Losses	(854)	(1,843)
Fair Value	182,888	480,318
Gross Unrealized Losses	(1,083)	(5,652)
Fixed maturities | Corporate bonds
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	120,114	395,399
Less than 12 months Gross Unrealized Losses	(622)	(10,114)
Greater than 12 months Fair Value	23,053	13,849
Greater than 12 months Gross Unrealized Losses	(732)	(624)
Fair Value	143,167	409,248
Gross Unrealized Losses	(1,354)	(10,738)
Equity Securities
Gain (Loss) on Investments [Line Items]
Less than 12 months Fair Value	38,050	58,531
Less than 12 months Gross Unrealized Losses	(1,490)	(3,013)
Greater than 12 months Fair Value	4,723
Greater than 12 months Gross Unrealized Losses	(277)
Fair Value	42,773	58,531
Gross Unrealized Losses	$ (1,767)	$ (3,013)

Summary of Cumulative Amounts R

Summary of Cumulative Amounts Related to Credit Loss Portion of Other-Than-Temporary Impairment Losses on Debt Securities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Investments Debt And Equity Securities [Abstract]
Beginning balance	$ 2,511	$ 2,361	$ 2,361	$ 2,361
Additions for credit loss impairments recognized in the current period on securities not previously impaired	0	0	150	0
Additions for credit loss impairments recognized in the current period on securities previously impaired	0	0	0	0
Reductions for credit loss impairments previously recognized on securities sold during the period	(150)	0	(150)	0
Ending balance	$ 2,361	$ 2,361	$ 2,361	$ 2,361

Net Investment Income (Detail)

Net Investment Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net Investment Income [Line Items]
Investment Income	$ 20,734	$ 18,168	$ 61,767	$ 52,647
Investment expenses	(859)	(797)	(2,423)	(2,428)
Net investment income	19,875	17,371	59,344	50,219
Fixed maturities
Net Investment Income [Line Items]
Investment Income	17,124	15,353	50,781	45,660
Equity Securities
Net Investment Income [Line Items]
Investment Income	3,540	2,543	10,418	6,383
Short-term investments
Net Investment Income [Line Items]
Investment Income	$ 70	$ 272	$ 568	$ 604

Realized Gains and Losses, Excl

Realized Gains and Losses, Excluding Net Other-Than-Temporary Impairment Losses Recognized in Earnings (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Gain (Loss) on Investments [Line Items]
Net realized gains (losses)	$ 1,586	$ 518	$ 5,143	$ 10,453
Fixed maturities
Gain (Loss) on Investments [Line Items]
Gains	1,356	484	5,200	2,889
Losses	(1,221)	(667)	(3,086)	(2,757)
Net realized gains (losses)	135	(183)	2,114	132
Short-term investments
Gain (Loss) on Investments [Line Items]
Gains	128	9	803	109
Losses	(107)	(120)	(250)	(273)
Net realized gains (losses)	21	(111)	553	(164)
Equity Securities
Gain (Loss) on Investments [Line Items]
Gains	1,443	1,107	3,123	12,185
Losses	(13)	(295)	(647)	(1,700)
Net realized gains (losses)	$ 1,430	$ 812	$ 2,476	$ 10,485

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Significant transfers between Level 1 and Level 2	$ 0	$ 0
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Level 3 assets	$ 0
5.75% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate stated on senior notes	5.75%
Senior notes due date	Oct. 15, 2023

Fixed Maturities and Equity Sec

Fixed Maturities and Equity Securities by Asset Class that are Measured at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	$ 3,139,388	$ 2,937,226
Total liabilities measured at fair value	294,080	282,486
Other Invested Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	2,021
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	348,395	411,594
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	2,788,972	2,525,632
Total liabilities measured at fair value	294,080	282,486
Fair Value Based on Net Asset Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	2,021
Fair Value Based on Net Asset Value | Other Invested Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	2,021
Fixed maturities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	2,660,417	2,414,210
Fixed maturities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	55,159	67,394
Fixed maturities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	2,605,258	2,346,816
Fixed maturities | U.S. Treasury bonds, agency bonds, and foreign
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	262,030	252,882
Fixed maturities | U.S. Treasury bonds, agency bonds, and foreign | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	55,159	67,394
Fixed maturities | U.S. Treasury bonds, agency bonds, and foreign | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	206,871	185,488
Fixed maturities | States, municipalities and political subdivisions
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	580,324	576,859
Fixed maturities | States, municipalities and political subdivisions | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	580,324	576,859
Fixed maturities | Agency mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	526,069	379,269
Fixed maturities | Agency mortgage-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	526,069	379,269
Fixed maturities | Residential Mortgage Backed Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	27,055	30,465
Fixed maturities | Residential Mortgage Backed Securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	27,055	30,465
Fixed maturities | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	288,636	225,012
Fixed maturities | Asset-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	288,636	225,012
Fixed maturities | Commercial mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	165,405	189,713
Fixed maturities | Commercial mortgage-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	165,405	189,713
Fixed maturities | Mortgage-backed and asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	1,007,165	824,459
Fixed maturities | Mortgage-backed and asset-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	1,007,165	824,459
Fixed maturities | Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	810,898	760,010
Fixed maturities | Corporate bonds | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	810,898	760,010
Equity Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	342,677	305,271
Equity Securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	158,963	126,455
Equity Securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	183,714	178,816
Short-term investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	134,273	217,745
Short-term investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities and equity securities, at fair Value	134,273	217,745
Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes, at fair value	294,080	282,486
Senior Notes | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes, at fair value	$ 294,080	$ 282,486

Ceded Reinsurance - Additional

Ceded Reinsurance - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Insurance [Abstract]
Reinsurance recoverables	$ 1,100
Reserve for uncollectible reinsurance amount	$ 10.4	$ 6.9

Commitments, Contingencies & Gu

Commitments, Contingencies & Guarantees - Additional Information (Detail) - USD ($) $ in Millions	Oct. 20, 2015	Sep. 30, 2013	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Incentive awarded to the company by the State of Connecticut, total				$ 11.5
Incentive awarded to the company by the State of Connecticut, non-interest bearing loans		$ 6		8
Incentive awarded to the company by the State of Connecticut, grants		1.5		$ 3.5
Non-interest bearing incentive loan term				10 years
Forgiveness awarded to the company by the state of Connecticut	$ 6			$ 6
Additional forgiveness awarded to the company by the state of Connecticut	1			1
Forgiveness awarded to the company by the State of Connecticut, grants	$ 0.5			0.5
Incentive awarded to the company by the State of Connecticut, revenue recognized			$ 0.4	1.1
Incentive awarded to the company by the State of Connecticut, deferred revenue		$ 7.5	$ 5.1	$ 5.1	$ 6.3

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016$ / sharesshares
Options and Non Performance Based Grants | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment award, award vesting period	3 years
Options and Non Performance Based Grants | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment award, award vesting period	4 years
Options expiration term (in years)	10 years
Stock incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive units granted | shares	216,973
Stock incentive Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive unit, grant price	$ 80.98
Stock incentive Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive unit, grant price	$ 92.56

Stockholders Equity - Additiona

Stockholders Equity - Additional Information (Detail) - $ / shares	Sep. 30, 2016	Jul. 15, 2016	Sep. 30, 2016
Stockholders Equity [Line Items]
Dividend declaration date			May 26, 2016
Installment 1 - FY 2016
Stockholders Equity [Line Items]
Common stock dividend paid per share		$ 0.09
Cash Dividend Paid Date			Jul. 15, 2016
Dividend payable record date			Jun. 20, 2016
Installment 2 - FY 2016
Stockholders Equity [Line Items]
Common stock dividend paid per share	$ 0.09
Cash Dividend Paid Date			Sep. 30, 2016
Dividend payable record date			Aug. 19, 2016

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - $ / shares	Nov. 03, 2016	Sep. 30, 2016
Subsequent Event [Line Items]
Dividend declaration date		May 26, 2016
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividend declaration date	Nov. 3, 2016
Dividend payable date	Dec. 29, 2016
Dividend payable record date	Nov. 18, 2016
Common stock dividend declared per share	$ 0.09