Investments Unrealized Losses Less Than and Greater Than 12 Months (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) security	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) security
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	$ 1,900,000.0	$ 0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 5,716,000		$ 7,934,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	128		218
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	$ 1,680,000		$ 2,383,000
Debt Securities In Continuous Loss Less Than 12 Months Fair Value	113,223,000		286,213,000
Debt Securities, Continuous Unrealized Loss Position for Less Than 12 Months	$ 2,959,000		$ 7,220,000
Debt Securities In Unrealized Loss Positions Qualitative Disclosure, Number Of Positions, Less Than 12 Months | security	114		263
Debt Securities In Continuous Loss Position 12 Months Or Longer, Fair Value	$ 34,870,000		$ 20,638,000
Debt Securities, Continuous Unrealized Loss Position for Greater Than 12 Months	$ 4,437,000		$ 3,097,000
Debt Securities In Unrealized Loss Positions Qualitative Disclosure, Number Of Positions,12 Months Or Greater | security	44		25
Debt Securities In Continuous Loss Position, Aggregate Fair Value	$ 148,093,000		$ 306,851,000
Debt Securities, Gross Unrealized and Unrecognized Losses	$ 7,396,000		$ 10,317,000
Debt Securities In Unrealized Loss Positions Qualitative Disclosure, Number Of Positions | security	158		288
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 0		$ 0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0		0
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	52,802,000		136,862,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 400,000		$ 1,474,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	47		129
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 15,061,000		$ 12,633,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1,833,000		$ 1,611,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	19		12
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 67,863,000		$ 149,495,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 2,233,000		$ 3,085,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	66		141
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 9,813,000		$ 74,628,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 115,000		$ 774,000
Number of Held to Maturity Securities In Continuous Loss Position Less Than 12 Months | security	15		59
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 10,136,000		$ 2,404,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 228,000		$ 109,000
Number of Held to Maturity Securities In Continuous Loss Position 12 Months or Greater | security	10		5
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	$ 19,949,000		$ 77,032,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	$ 343,000		$ 883,000
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	25		64
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 48,931,000		$ 70,081,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 2,309,000		$ 4,330,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	50		69
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 4,861,000		$ 3,308,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1,172,000		$ 517,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	8		3
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 53,792,000		$ 73,389,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 3,481,000		$ 4,847,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	58		72
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 1,624,000		$ 4,585,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 134,000		$ 641,000
Number of Held to Maturity Securities In Continuous Loss Position Less Than 12 Months | security	1		4
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 4,682,000		$ 2,160,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1,203,000		$ 859,000
Number of Held to Maturity Securities In Continuous Loss Position 12 Months or Greater | security	4		2
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	$ 6,306,000		$ 6,745,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	$ 1,337,000		$ 1,500,000
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	5		6
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 0		$ 0
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	53,000		57,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 1,000		$ 1,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	1		2
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 130,000		$ 133,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1,000		$ 1,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	3		3
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 183,000		$ 190,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 2,000		$ 2,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	4		5
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 101,786,000		$ 207,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 2,710,000		$ 5,805,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	98		200
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 20,052,000		$ 16,074,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 3,006,000		$ 2,129,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	30		18
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 121,838,000		$ 223,074,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	5,716,000		7,934,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	11,437,000		79,213,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 249,000		$ 1,415,000
Number of Held to Maturity Securities In Continuous Loss Position Less Than 12 Months | security	16		63
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 14,818,000		$ 4,564,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1,431,000		$ 968,000
Number of Held to Maturity Securities In Continuous Loss Position 12 Months or Greater | security	14		7
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	$ 26,255,000		$ 83,777,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	$ 1,680,000		$ 2,383,000
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	30		70
Stock Mutual Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 3,073,000		$ 3,030,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 195,000		$ 237,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	4		4
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 2,000		$ 2,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0		$ 0
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	1		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 3,075,000		$ 3,032,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 195,000		$ 237,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	5		5
Bond Mutual Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 10,196,000		$ 10,158,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 280,000		$ 318,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	2		2
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 105,000		$ 108,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 35,000		$ 31,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	1		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 10,301,000		$ 10,266,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 315,000		$ 349,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	3		3
Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 0		$ 22,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 0		$ 1,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	0		2
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 16,000		$ 21,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 25,000		$ 21,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	2		2
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 16,000		$ 43,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 25,000		$ 22,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	2		4
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 0		$ 101,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 0		$ 1,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	0		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 0		$ 1,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1,000		$ 1,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	1		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 0		$ 102,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 1,000		$ 2,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	1		2
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 13,269,000		$ 13,311,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 475,000		$ 557,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | security	6		9
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 123,000		$ 132,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 61,000		$ 53,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	5		5
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 13,392,000		$ 13,443,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 536,000		$ 610,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	11		14