Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fixed maturities [Abstract]
Total fixed maturities	$ 469,015	$ 491,904
Equity securities [Abstract]
Total equity securities	187,917	119,945
Recurring [Member]
Fixed maturities [Abstract]
Agency collateralized mortgage obligations	7,927	6,171
Agency mortgage-backed securities	15,852	4,770
Asset-backed securities	41,543	45,183
Bank loans	21,557	10,349
Certificates of deposit	3,127	3,117
Collateralized mortgage obligations	6,590	9,104
Corporate securities	146,521	137,932
Options embedded in convertible securities	5,153	4,751
Mortgage-backed securities	23,962	24,571
Municipal obligations	112,717	129,335
Non-U.S. government obligations	27,095	24,681
U.S. government obligations	56,971	91,940
Total fixed maturities	469,015	491,904
Equity securities [Abstract]
Consumer	43,293	32,576
Energy	7,630	12,842
Financial	43,169	31,186
Industrial	29,069	21,145
Technology	9,507	8,858
Mutual fund	48,492	6,995
Other	6,757	6,343
Total equity securities	187,917	119,945
Short-term	1,500	1,500
Cash equivalents	77,298	59,683
Total fair value	735,730	673,032
Recurring [Member] | Level 1 [Member]
Fixed maturities [Abstract]
Agency collateralized mortgage obligations	0	0
Agency mortgage-backed securities	0	0
Asset-backed securities	0	0
Bank loans	0	0
Certificates of deposit	3,127	3,117
Collateralized mortgage obligations	0	0
Corporate securities	0	0
Options embedded in convertible securities	0	0
Mortgage-backed securities	0	0
Municipal obligations	0	0
Non-U.S. government obligations	3,261	0
U.S. government obligations	0	0
Total fixed maturities	6,388	3,117
Equity securities [Abstract]
Consumer	43,293	32,576
Energy	7,630	12,842
Financial	43,169	30,943
Industrial	28,093	20,262
Technology	9,507	8,858
Mutual fund	48,492	0
Other	6,757	6,343
Total equity securities	186,941	111,824
Short-term	1,500	1,500
Cash equivalents	0	0
Total fair value	194,829	116,441
Recurring [Member] | Level 2 [Member]
Fixed maturities [Abstract]
Agency collateralized mortgage obligations	7,927	6,171
Agency mortgage-backed securities	15,852	4,770
Asset-backed securities	37,748	37,919
Bank loans	0	0
Certificates of deposit	0	0
Collateralized mortgage obligations	5,593	6,409
Corporate securities	145,695	135,794
Options embedded in convertible securities	5,153	4,751
Mortgage-backed securities	22,141	22,206
Municipal obligations	112,503	129,190
Non-U.S. government obligations	23,834	24,419
U.S. government obligations	56,971	91,940
Total fixed maturities	433,417	463,569
Equity securities [Abstract]
Consumer	0	0
Energy	0	0
Financial	0	243
Industrial	976	883
Technology	0	0
Mutual fund	0	6,995
Other	0	0
Total equity securities	976	8,121
Short-term	0	0
Cash equivalents	77,298	59,683
Total fair value	511,691	531,373
Recurring [Member] | Level 3 [Member]
Fixed maturities [Abstract]
Agency collateralized mortgage obligations	0	0
Agency mortgage-backed securities	0	0
Asset-backed securities	3,795	7,264
Bank loans	21,557	10,349
Certificates of deposit	0	0
Collateralized mortgage obligations	997	2,695
Corporate securities	826	2,138
Options embedded in convertible securities	0	0
Mortgage-backed securities	1,821	2,365
Municipal obligations	214	145
Non-U.S. government obligations	0	262
U.S. government obligations	0	0
Total fixed maturities	29,210	25,218
Equity securities [Abstract]
Consumer	0	0
Energy	0	0
Financial	0	0
Industrial	0	0
Technology	0	0
Mutual fund	0	0
Other	0	0
Total equity securities	0	0
Short-term	0	0
Cash equivalents	0	0
Total fair value	$ 29,210	$ 25,218