Related Party Transactions (Affiliated Asset Transfers) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Gibraltar Life Insurance Co Ltd August-16 Sale
Related Party Transaction [Line Items]
Fair Value	$ 11,559
Book Value	11,485
Additional Paid-in Capital, Net of Tax Increase/ (Decrease)	0
Realized Investment Gain/ (Loss), Net of Tax	48
Prudential Insurance September-16 Sale
Related Party Transaction [Line Items]
Fair Value	47,066
Book Value	36,639
Additional Paid-in Capital, Net of Tax Increase/ (Decrease)	0
Realized Investment Gain/ (Loss), Net of Tax	6,777
Pruco Re September-16 Transfer in
Related Party Transaction [Line Items]
Fair Value	91,586
Book Value	80,732
Additional Paid-in Capital, Net of Tax Increase/ (Decrease)	(7,055)
Realized Investment Gain/ (Loss), Net of Tax	$ 0