Investments (Other Than Temporary Impairments by Asset Type) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($) Securities	Sep. 30, 2015 USD ($) Securities	Sep. 30, 2016 USD ($) Securities	Sep. 30, 2015 USD ($) Securities
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		4	17	8
Total OTTI losses	$ (4,554)	$ (10,000)	$ (11,334)	$ (10,132)
Portion of OTTI losses recognized in (from) other comprehensive income	1,575	4,771	(1,785)	3,943
Net OTTI losses recognized in operations	$ (2,979)	$ (5,229)	$ (13,119)	$ (6,189)
Corporate Securities [Member] | Energy [Member]
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities			2
Total OTTI losses			$ (642)
Portion of OTTI losses recognized in (from) other comprehensive income			0
Net OTTI losses recognized in operations			$ (642)
Corporate Securities [Member] | Materials [Member]
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities	1		1
Total OTTI losses	$ (4,554)		$ (4,554)
Portion of OTTI losses recognized in (from) other comprehensive income	1,575		1,575
Net OTTI losses recognized in operations	$ (2,979)		$ (2,979)
Corporate Securities [Member] | Telecommunications [Member]
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities			1
Total OTTI losses			$ (4,462)
Portion of OTTI losses recognized in (from) other comprehensive income			562
Net OTTI losses recognized in operations			$ (3,900)
Corporate Securities [Member] | Utilities [Member]
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities			1
Total OTTI losses			$ (136)
Portion of OTTI losses recognized in (from) other comprehensive income			0
Net OTTI losses recognized in operations			$ (136)
Residential Mortgage Backed Securities [Member]
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		3	6	7
Total OTTI losses		$ 0	$ 0	$ (132)
Portion of OTTI losses recognized in (from) other comprehensive income		(354)	(440)	(1,182)
Net OTTI losses recognized in operations		$ (354)	$ (440)	$ (1,314)
Commercial Mortgage Backed Securities [Member]
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities			5
Total OTTI losses			$ (1,540)
Portion of OTTI losses recognized in (from) other comprehensive income			0
Net OTTI losses recognized in operations			$ (1,540)
Other Asset Backed Securities [Member]
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		1	1	1
Total OTTI losses		$ (10,000)	$ 0	$ (10,000)
Portion of OTTI losses recognized in (from) other comprehensive income		5,125	(3,482)	5,125
Net OTTI losses recognized in operations		$ (4,875)	$ (3,482)	$ (4,875)