Schedule I - Summary of Investments-Other Than Investments In Related Parties (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	$ 3,562,470
Fair Value	3,758,990
Amount Which is Presented in the Balance Sheet	3,650,130
U.S. Government or government agencies and authorities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	148,311
Fair Value	150,226
Amount Which is Presented in the Balance Sheet	150,226
States, municipalities and political subdivisions [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	904,719
Fair Value	940,635
Amount Which is Presented in the Balance Sheet	940,635
Foreign governments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	5,128
Fair Value	5,256
Amount Which is Presented in the Balance Sheet	5,256
Public utilities bonds [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	95,185
Fair Value	96,448
Amount Which is Presented in the Balance Sheet	96,448
All other corporate bonds [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	1,195,665
Fair Value	1,189,832
Amount Which is Presented in the Balance Sheet	1,189,832
Certificates of deposit [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	150
Fair Value	150
Amount Which is Presented in the Balance Sheet	150
Mortgage-backed securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	372,905
Fair Value	377,740
Amount Which is Presented in the Balance Sheet	377,740
Fixed Maturities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	2,722,063
Fair Value	2,760,287
Amount Which is Presented in the Balance Sheet	2,760,287
Public utilities equity, trading [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	9,546
Fair Value	9,518
Amount Which is Presented in the Balance Sheet	9,518
Banks, trusts and insurance companies, trading [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	68,639
Fair Value	67,764
Amount Which is Presented in the Balance Sheet	67,764
Industrial, miscellaneous and all other, trading [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	241,135
Fair Value	245,071
Amount Which is Presented in the Balance Sheet	245,071
Total Equity Securities, trading [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	319,320
Fair Value	322,353
Amount Which is Presented in the Balance Sheet	322,353
Other long-term investments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	401,851
Fair Value	557,114
Amount Which is Presented in the Balance Sheet	448,254
Short-term Investments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Recorded Cost Basis	119,236
Fair Value	119,236
Amount Which is Presented in the Balance Sheet	$ 119,236

This element represents the carrying (reported) amount of the entity's investments as of the balance sheet date. This amount may represent the individual investment's or group of similar investments' original cost, fair value, or such other amount at which the investment is shown in the entity's balance sheet.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 7
-Subparagraph (SX 210.12-15)
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010

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