Investments (Net Unrealized Gains Losses on Investments by Asset Class) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Net unrealized gains (losses) on investments	$ 213,265		$ 198,923
Fixed Maturities [Member]
Net unrealized gains (losses) on investments	197,392		191,339
Equity Securities [Member]
Net unrealized gains (losses) on investments	3		3
Other Long-term Investments [Member]
Net unrealized gains (losses) on investments	356		390
Affiliated Notes [Member]
Net unrealized gains (losses) on investments	2,348		2,351
Securities Related to Other Than Temporary Impairments [Member] | Fixed Maturities [Member]
Net unrealized gains (losses) on investments	3		1
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Net unrealized gains (losses) on investments	$ 13,163	[1]	$ 4,839	[1]

[1] See Note 5 for more information on cash flow hedges.