Fair Value Disclosures - Level 3 Roll Forward (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Net Asset (Liability) Value [Roll Forward]
Balance at December 31, 2015	$ 0
Purchases/additions	2,211
Sales	0
Payments received	(65)
Premium amortization, net	0
(Decrease) increase in value	(17)
Transfer into Level 3	28,778
Balance at December 31, 2016	30,907
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, 2015	0
Purchases/additions	(102)
Sales	0
Payments received	0
Premium amortization, net	0
(Decrease) increase in value	93
Transfer into Level 3	0
Balance at December 31, 2016	(9)
Corporate Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2015	0
Purchases/additions	0
Sales	0
Payments received	0
Premium amortization, net	0
(Decrease) increase in value	0
Transfer into Level 3	28,778
Balance at December 31, 2016	28,778
Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2015	0
Purchases/additions	2,313
Sales	0
Payments received	(65)
Premium amortization, net	0
(Decrease) increase in value	(110)
Transfer into Level 3	0
Balance at December 31, 2016	$ 2,138