SCHEDULE I-SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	$ 4,951,451
Fair Value	4,866,819
Amount at which shown in the balance sheet	4,866,819
Equity Securities, Common Stocks [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	2,908
Fair Value	2,894
Amount at which shown in the balance sheet	2,894
Equity Securities, Common Stocks [Member] | Industrial, Miscellaneous, and All Others [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	2,908
Fair Value	2,894
Amount at which shown in the balance sheet	2,894
Fixed Maturities, Bonds [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	4,948,543
Fair Value	4,863,925
Amount at which shown in the balance sheet	4,863,925
Fixed Maturities, Bonds [Member] | US Government and Government Agencies and Authorities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	663,642
Fair Value	639,590
Amount at which shown in the balance sheet	639,590
Fixed Maturities, Bonds [Member] | States, Municipalities and Political Subdivisions [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	932,922
Fair Value	921,367
Amount at which shown in the balance sheet	921,367
Fixed Maturities, Bonds [Member] | Foreign Governments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	39,420
Fair Value	40,852
Amount at which shown in the balance sheet	40,852
Fixed Maturities, Bonds [Member] | Public Utilities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	220,788
Fair Value	219,018
Amount at which shown in the balance sheet	219,018
Fixed Maturities, Bonds [Member] | Asset-Backed Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	399,839
Fair Value	400,486
Amount at which shown in the balance sheet	400,486
Fixed Maturities, Bonds [Member] | Collateralized Loan Obligations [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	61,337
Fair Value	60,295
Amount at which shown in the balance sheet	60,295
Fixed Maturities, Bonds [Member] | Mortgage Backed Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	661,288
Fair Value	629,920
Amount at which shown in the balance sheet	629,920
Fixed Maturities, Bonds [Member] | All Other Corporate Bonds [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	1,969,307
Fair Value	1,952,397
Amount at which shown in the balance sheet	$ 1,952,397