Fair Value of Assets and Liabilities 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]	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Equity, Level 1 to Level 2 Transfers, Description	0	0	0	625
Fair Value, Equity, Level 2 to Level 1 Transfers, Description	0	31896	0	36996