Retirement and Compensation Plans Other retirement plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Cost Recognized	$ 2,400	$ 2,200	$ 2,000
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ 1,578	(2,791)	2,778	[1]
Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, employer discretionary percentage	2.75%
Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, employer discretionary percentage	5.75%
Defined Contribution Plan Grandfathered Choice Participant [Member] | Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	2.00%
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	2.00%
Pension Plan [Member] | Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	4.00%
Health and medical post retirement plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	$ (100)	100	100
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(100)	$ (100)	$ 0
Defined Benefit Plan, Effect of Curtailments on Accumulated Benefit Obligation	$ 200

[1] Other comprehensive income (loss) is recorded net of deferred income taxes and other adjustments for assumed changes in deferred acquisition costs, value of insurance in force acquired, unearned revenue reserve and policyholder liabilities.