Investments (All Other Net Unrealized Investment Gains and Losses in AOCI) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, Beginning of Period	$ 64,805
Balance, End of Period	249,787
Other Net Unrealized Investment Gains and Losses | Net Unrealized Gains (Losses) on Investments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, Beginning of Period	111,837
Net investment gains (losses) on investments arising during the period	353,495
Reclassification adjustment for (gains) losses included in net income	(70,941)
Reclassification adjustment for OTTI losses excluded from net income	512
Impact of net unrealized investment (gains) losses on deferred policy acquisition costs and other costs	0
Impact of net unrealized investment (gains) losses on future policy benefits and policyholders’ account balances	0
Balance, End of Period	394,903
Other Net Unrealized Investment Gains and Losses | Deferred Policy Acquisition Costs and Other Costs
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, Beginning of Period	(19,252)
Net investment gains (losses) on investments arising during the period	0
Reclassification adjustment for (gains) losses included in net income	0
Reclassification adjustment for OTTI losses excluded from net income	0
Impact of net unrealized investment (gains) losses on deferred policy acquisition costs and other costs	(76,187)
Impact of net unrealized investment (gains) losses on future policy benefits and policyholders’ account balances	0
Balance, End of Period	(95,439)
Other Net Unrealized Investment Gains and Losses | Future Policy Benefits and Policyholders’ Account Balances
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, Beginning of Period	2,647
Net investment gains (losses) on investments arising during the period	0
Reclassification adjustment for (gains) losses included in net income	0
Reclassification adjustment for OTTI losses excluded from net income	0
Impact of net unrealized investment (gains) losses on deferred policy acquisition costs and other costs	0
Impact of net unrealized investment (gains) losses on future policy benefits and policyholders’ account balances	78,322
Balance, End of Period	80,969
Other Net Unrealized Investment Gains and Losses | Deferred Income Tax (Liability) Benefit
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, Beginning of Period	(33,223)
Net investment gains (losses) on investments arising during the period	(123,722)
Reclassification adjustment for (gains) losses included in net income	24,829
Reclassification adjustment for OTTI losses excluded from net income	(179)
Impact of net unrealized investment (gains) losses on deferred policy acquisition costs and other costs	26,665
Impact of net unrealized investment (gains) losses on future policy benefits and policyholders’ account balances	(27,413)
Balance, End of Period	(133,043)
Other Net Unrealized Investment Gains and Losses | Total net unrealized investment gains (losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, Beginning of Period	62,009
Net investment gains (losses) on investments arising during the period	229,773
Reclassification adjustment for (gains) losses included in net income	(46,112)
Reclassification adjustment for OTTI losses excluded from net income	333
Impact of net unrealized investment (gains) losses on deferred policy acquisition costs and other costs	(49,522)
Impact of net unrealized investment (gains) losses on future policy benefits and policyholders’ account balances	50,909
Balance, End of Period	$ 247,390