SCHEDULE II CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments other than subsidiaries [Abstract]
Fixed income securities												$ 592,645	$ 521,853
Limited partnerships												55,044	70,806
Total Investments												721,783	795,422
Cash and cash equivalents	$ 163,996			$ 64,680	$ 64,680				$ 163,996	$ 64,680		163,996	64,680
Accounts receivable												102,972	87,551
Other assets												24,760	18,399
Total Assets												1,490,131	1,357,016
Liabilities [Abstract]
Short-term borrowings												20,000	20,000
Total Liabilities												1,134,049	938,205
Shareholders' equity [Abstract]
Additional paid-in capital												54,720	55,078
Accumulated other comprehensive income (loss)												(7,347)	46,391
Retained earnings												308,075	316,700
Shareholders' equity												356,082	418,811	$ 404,345	$ 394,498
Total liabilities and shareholders' equity												1,490,131	1,357,016
Revenue [Abstract]
Net investment income	6,038	$ 5,578	$ 5,796	4,636	5,661	$ 4,027	$ 4,716	$ 3,692	22,048	18,095	$ 14,483
Net realized gains (losses) on investments	(20,096)	2,373	(3,435)	(4,533)	4,152	5,944	3,296	6,294	(25,691)	19,686	23,228
Total revenues									439,169	371,234	318,997
Expenses [Abstract]
Other									137,177	113,594	89,462
Total expenses									483,041	361,112	275,943
Federal income tax benefit									(9,797)	(8,201)	14,109
Net income (loss)	(24,567)	(12,325)	2,487	330	16,476	7,434	(12,343)	6,756	(34,075)	18,323	28,945
Condensed Statements of Comprehensive Income [Abstract]
Net income (loss)	(24,567)	$ (12,325)	$ 2,487	330	16,476	$ 7,434	$ (12,343)	6,756	(34,075)	18,323	28,945
Unrealized net gains (losses) on fixed income securities:
Unrealized net gains (losses) arising during the period									(9,680)	17,340	8,618
Less: reclassification adjustment for net gains (losses) included in net income (loss)									(2,812)	4,691	13,491
Change in unrealized gains (losses) on investments									(6,868)	12,649	(4,873)
Foreign currency translation adjustments									(830)	522	235
Other comprehensive income (loss)									(7,698)	13,171	(4,638)
Comprehensive income (loss)									(41,773)	31,494	24,307
Condensed Statements of Cash Flows [Abstract]
Net cash provided by operating activities									100,708	97,744	32,368
Investing activities [Abstract]
Net sales of short-term investments									0	500	11,258
Distributions from limited partnerships									6,869	19,230	1,462
Net purchases of property and equipment									(5,439)	(6,661)	(7,725)
Net cash provided by (used in) investing activities									23,651	(74,347)	(27,362)
Financing activities [Abstract]
Dividends paid to shareholders									(16,835)	(16,302)	(15,803)
Repurchase of common shares									(4,596)	(1,880)	0
Net cash used in financing activities									(21,431)	(18,182)	(15,803)
Increase (decrease) in cash, cash equivalents and restricted cash and cash equivalents									102,098	5,737	(10,562)
Cash, cash equivalents and restricted cash and cash equivalents at beginning of year				64,680					64,680
Cash, cash equivalents and restricted cash and cash equivalents at end of year	163,996				64,680				163,996	64,680
Class A [Member]
Shareholders' equity [Abstract]
Common stock												112	112
Class B [Member]
Shareholders' equity [Abstract]
Common stock												522	530
Baldwin & Lyons, Inc. [Member]
Assets [Abstract]
Investment in subsidiaries												401,260	436,879
Due from affiliates												1,152	1,191
Investments other than subsidiaries [Abstract]
Fixed income securities												22,302	22,306
Limited partnerships												215	222
Total Investments												22,517	22,528
Cash and cash equivalents	15,185			26,496	26,496			14,995	15,185	26,496	14,995	15,185	26,496	$ 14,995	$ 17,934
Accounts receivable												2,276	6,833
Other assets												28,794	24,772
Total Assets												471,184	518,699
Liabilities [Abstract]
Premiums payable												22,964	14,046
Deposits from insureds												58,748	60,893
Short-term borrowings												20,000	20,000
Other liabilities												13,390	4,949
Total Liabilities												115,102	99,888
Shareholders' equity [Abstract]
Additional paid-in capital												54,720	55,078
Accumulated other comprehensive income (loss)												(7,347)	46,391
Retained earnings												308,075	316,700
Shareholders' equity												356,082	418,811
Total liabilities and shareholders' equity												471,184	518,699
Revenue [Abstract]
Commissions and service fees									17,456	18,863	27,736
Cash dividends from subsidiaries									5,000	10,000	20,000
Net investment income									569	348	134
Net realized gains (losses) on investments									(192)	308	(3)
Other									51	(106)	(24)
Total revenues									22,884	29,413	47,843
Expenses [Abstract]
Salary and related items									20,158	18,140	17,462
Other									11,724	9,686	10,808
Total expenses									31,882	27,826	28,270
Income (loss) before federal income tax benefit and equity in undistributed income of subsidiaries									(8,998)	1,587	19,573
Federal income tax benefit									(2,862)	(2,971)	(69)
Income after federal income taxes and equity in undistributed income of subsidiaries									(6,136)	4,558	19,642
Equity in undistributed income of subsidiaries									(27,939)	13,765	9,303
Net income (loss)									(34,075)	18,323	28,945
Condensed Statements of Comprehensive Income [Abstract]
Net income (loss)									(34,075)	18,323	28,945
Unrealized net gains (losses) on fixed income securities:
Unrealized net gains (losses) arising during the period									(9,680)	17,340	8,618
Less: reclassification adjustment for net gains (losses) included in net income (loss)									(2,812)	4,691	13,491
Change in unrealized gains (losses) on investments									(6,868)	12,649	(4,873)
Foreign currency translation adjustments									(830)	522	235
Other comprehensive income (loss)									(7,698)	13,171	(4,638)
Comprehensive income (loss)									(41,773)	31,494	24,307
Condensed Statements of Cash Flows [Abstract]
Net cash provided by operating activities									14,019	44,998	15,484
Investing activities [Abstract]
Purchases of investments									(11,435)	(21,365)	(4,000)
Sales or maturities of investments									11,213	9,146	3,493
Net sales of short-term investments									0	0	2,165
Distributions from limited partnerships									0	298	0
Net purchases of property and equipment									(3,677)	(3,394)	(4,278)
Net cash provided by (used in) investing activities									(3,899)	(15,315)	(2,620)
Financing activities [Abstract]
Dividends paid to shareholders									(16,835)	(16,302)	(15,803)
Repurchase of common shares									(4,596)	(1,880)	0
Net cash used in financing activities									(21,431)	(18,182)	(15,803)
Increase (decrease) in cash, cash equivalents and restricted cash and cash equivalents									(11,311)	11,501	(2,939)
Cash, cash equivalents and restricted cash and cash equivalents at beginning of year				$ 26,496				$ 14,995	26,496	14,995	17,934
Cash, cash equivalents and restricted cash and cash equivalents at end of year	$ 15,185				$ 26,496				$ 15,185	$ 26,496	$ 14,995
Baldwin & Lyons, Inc. [Member] | Class A [Member]
Shareholders' equity [Abstract]
Common stock												112	112
Baldwin & Lyons, Inc. [Member] | Class B [Member]
Shareholders' equity [Abstract]
Common stock												$ 522	$ 530