Investments Gross Unrealized Gains and Losses (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	$ 784,934,000	$ 784,934,000		$ 714,137,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	53,374,000	53,374,000		29,445,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	2,835,000	2,835,000		7,934,000
Available-for-sale Securities, Debt Securities	835,473,000	835,473,000		735,648,000
Held-to-maturity Securities [Abstract]
Held-to-maturity Securities	256,165,000	256,165,000		259,953,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	14,835,000	14,835,000		7,396,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	949,000	949,000		2,383,000
Held-to-maturity Securities, Fair Value	270,051,000	270,051,000		264,966,000
Total Fixed maturity securities, Amortized Cost	1,041,099,000	1,041,099,000		974,090,000
Debt Securities, Accumulative Gross Unrealized and Unrecognized Gains	68,209,000	68,209,000		36,841,000
Debt Securities, Accumulated Gross Unrealized and Unrecognized Losses	3,784,000	3,784,000		10,317,000
Total Fixed Maturity Securities, Fair Value	1,105,524,000	1,105,524,000		1,000,614,000
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract]
Available-for-sale Equity Securities, Amortized Cost Basis	22,729,000	22,729,000		23,727,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	523,000	523,000		321,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	18,000	18,000		610,000
Available-for-sale Securities, Equity Securities	23,234,000	23,234,000		23,438,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0.4	2.3	$ 0
US Treasury Securities [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	9,962,000	9,962,000		9,995,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	3,151,000	3,151,000		2,597,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		0
Available-for-sale Securities, Debt Securities	13,113,000	13,113,000		12,592,000
US Government Agencies Debt Securities [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	7,701,000	7,701,000		19,676,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,328,000	1,328,000		1,104,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		0
Available-for-sale Securities, Debt Securities	9,029,000	9,029,000		20,780,000
Held-to-maturity Securities [Abstract]
Held-to-maturity Securities	2,006,000	2,006,000		2,010,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	84,000	84,000		110,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0		0
Held-to-maturity Securities, Fair Value	2,090,000	2,090,000		2,120,000
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	514,576,000	514,576,000		470,319,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	30,297,000	30,297,000		15,815,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	1,522,000	1,522,000		3,085,000
Available-for-sale Securities, Debt Securities	543,351,000	543,351,000		483,049,000
Held-to-maturity Securities [Abstract]
Held-to-maturity Securities	233,058,000	233,058,000		236,776,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	13,708,000	13,708,000		6,756,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	96,000	96,000		883,000
Held-to-maturity Securities, Fair Value	246,670,000	246,670,000		242,649,000
Foreign Government Debt Securities [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	103,000	103,000		104,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	31,000	31,000		27,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		0
Available-for-sale Securities, Debt Securities	134,000	134,000		131,000
Corporate Debt Securities [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	250,041,000	250,041,000		211,245,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	18,334,000	18,334,000		9,683,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	1,310,000	1,310,000		4,847,000
Available-for-sale Securities, Debt Securities	267,065,000	267,065,000		216,081,000
Held-to-maturity Securities [Abstract]
Held-to-maturity Securities	21,101,000	21,101,000		21,167,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,043,000	1,043,000		530,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	853,000	853,000		1,500,000
Held-to-maturity Securities, Fair Value	21,291,000	21,291,000		20,197,000
Commercial Mortgage Backed Securities [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	103,000	103,000		140,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	5,000	5,000		5,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		0
Available-for-sale Securities, Debt Securities	108,000	108,000		145,000
Residential Mortgage Backed Securities [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	2,448,000	2,448,000		2,658,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	228,000	228,000		214,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	3,000	3,000		2,000
Available-for-sale Securities, Debt Securities	2,673,000	2,673,000		2,870,000
Short-term Investments [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	521,000	521,000		251,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	0		0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		0
Available-for-sale Securities, Debt Securities	521,000	521,000		251,000
Stock Mutual Funds [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	1,000	1,000		237,000
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract]
Available-for-sale Equity Securities, Amortized Cost Basis	2,867,000	2,867,000		3,270,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	0	0		0
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	1,000	1,000		237,000
Available-for-sale Securities, Equity Securities	2,866,000	2,866,000		3,033,000
Bond Mutual Funds [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		349,000
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract]
Available-for-sale Equity Securities, Amortized Cost Basis	18,451,000	18,451,000		18,798,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	301,000	301,000		55,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		349,000
Available-for-sale Securities, Equity Securities	18,752,000	18,752,000		18,504,000
Common Stock [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	17,000	17,000		22,000
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract]
Available-for-sale Equity Securities, Amortized Cost Basis	39,000	39,000		65,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	4,000	4,000		0
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	17,000	17,000		22,000
Available-for-sale Securities, Equity Securities	26,000	26,000		43,000
Preferred Stock [Member]
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		2,000
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract]
Available-for-sale Equity Securities, Amortized Cost Basis	1,372,000	1,372,000		1,594,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	218,000	218,000		266,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	0	0		2,000
Available-for-sale Securities, Equity Securities	$ 1,590,000	$ 1,590,000		$ 1,858,000