Fair Value of Assets and Liabilities (Fair Value Assets Transfers between Level 1 and Level 2) (Details) - Corporate Debt Securities [Member] - Available-for-sale Securities [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$ 32,206	$ 6,000
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	$ 127,653	$ 22,537