Investments (Schedule of Revenue and General Obligation Bonds by Location) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	$ 461,990	$ 424,315
Estimated Fair Value	467,688	425,044
States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	96,199	97,361
Estimated Fair Value	98,623	96,563
General Obligation Bonds [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	76,618	76,855
Estimated Fair Value	78,728	76,302
General Obligation Bonds [Member] \| California [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	20,026	20,638
Estimated Fair Value	21,219	21,272
General Obligation Bonds [Member] \| Texas [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	12,831	11,340
Estimated Fair Value	12,958	11,024
General Obligation Bonds [Member] \| Illinois [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	8,287	8,965
Estimated Fair Value	8,392	8,702
General Obligation Bonds [Member] \| Ohio [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	7,640	7,659
Estimated Fair Value	7,703	7,485
General Obligation Bonds [Member] \| Washington [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	5,981	5,487
Estimated Fair Value	6,109	5,340
General Obligation Bonds [Member] \| Arizona [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	2,077	2,100
Estimated Fair Value	2,417	2,050
General Obligation Bonds [Member] \| Other States [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	19,776	20,666
Estimated Fair Value	19,930	20,429
Revenue Bonds [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	19,581	18,233
Estimated Fair Value	19,895	17,931
Revenue Bonds [Member] \| California [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	2,219	2,519
Estimated Fair Value	2,284	2,579
Revenue Bonds [Member] \| Texas [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	3,284	2,762
Estimated Fair Value	3,394	2,719
Revenue Bonds [Member] \| Ohio [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	322	324
Estimated Fair Value	335	339
Revenue Bonds [Member] \| Washington [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	1,168	1,170
Estimated Fair Value	1,204	1,211
Revenue Bonds [Member] \| Arizona [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	4,617	4,700
Estimated Fair Value	4,508	4,341
Revenue Bonds [Member] \| Other States [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost	7,971	6,758
Estimated Fair Value	8,170	6,742
Certificates Of Participation [Member] \| States and political subdivisions [Member]
Investment Holdings, Other than Securities [Line Items]
Amortized Cost		2,273
Estimated Fair Value		$ 2,330