Fair Value Disclosures - Level 3 Roll Forward (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Net Asset (Liability) Value [Roll Forward]
Balance at December 31, 2016	$ 30,907
Purchases/additions	(120)
Sales	0
Payments received	(33)
Premium amortization, net	0
(Decrease) increase in value	(525)
Balance at March 31, 2017	30,229
Derivative Financial Instruments, Liabilities [Member] | Credit Risk Contract [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2016	(9)
Purchases/additions	(120)
Sales	0
Payments received	0
Premium amortization, net	0
(Decrease) increase in value	72
Balance at March 31, 2017	(57)
Corporate Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2016	28,778
Purchases/additions	0
Sales	0
Payments received	0
Premium amortization, net	0
(Decrease) increase in value	(584)
Balance at March 31, 2017	28,194
Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2016	2,138
Purchases/additions	0
Sales	0
Payments received	(33)
Premium amortization, net	0
(Decrease) increase in value	(13)
Balance at March 31, 2017	$ 2,092