Investments (Borrowed Securities Repurchased Securities And Repurchased Reversed Repurchased Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Securities for Reverse Repurchase Agreements	$ 454,264	$ 443,435
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	479,482	481,197
Reported Value Measurement [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Borrowed	268,800	259,540
Estimate of Fair Value Measurement [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Borrowed	282,780	266,297
Securities for Reverse Repurchase Agreements	$ 479,427	$ 465,889