The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the methods used to account for the allowance for premium cancellations for tax purposes and under generally accepted accounting principles. The difference in basis of such prepaid expenses will reduce future taxable income when such basis difference reverses.

No definition available.

Income Taxes (Details 3) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details 3) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Apr. 30, 2018	Jan. 31, 2018	Dec. 31, 2016
Deferred tax assets:
Other employee benefits		$ 14,092			$ 19,106
Pension and other postretirement benefits		22,758			65,241
Allowance for management fee returned on cancelled policies		3,024			4,795
Other		812			81
Total deferred tax assets		40,686			89,223
Deferred tax liabilities:
Depreciation		10,204			18,493
Prepaid expenses		5,568			8,120
Limited partnerships		4,509			5,597
Unrealized gains on investments		856			1,657
Other		159			1,467
Total deferred tax liabilities		21,296			35,334
Net deferred tax asset		$ 19,390			$ 53,889
Federal statutory income tax rate
Corporate tax rate		35.00%
Tax Cuts and Jobs Act of 2017 \| Scenario, Forecast
Federal statutory income tax rate
Corporate tax rate	21.00%
Employee pension plan \| Qualified plan \| Funded plan
Decrease in deferred tax assets due to pension contributions
Unplanned additional pension contributions in 2017		$ 39,900
Employee pension plan \| Qualified plan \| Funded plan \| Scenario, Forecast
Decrease in deferred tax assets due to pension contributions
Accelerated pension contributions in 2018			$ 40,000	$ 40,000