Fair Values of Financial Instruments (Quantitative Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	$ 2,966,555	$ 2,917,992
Financial and Nonfinancial Liabilities, Fair Value Disclosure	69,470	66,028
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	42,179	38,409
Financial and Nonfinancial Liabilities, Fair Value Disclosure	69,470	66,028
Derivatives, Index Options [Member] | Broker Prices [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	42,179	38,409
Policyholders Account Balance [Member] | Deterministic Cash Flow [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	63,308	58,359
Other Liabilities [Member] | Black Scholes [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 6,162	$ 7,669