Fair Value Measurements (Details 5) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	3 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total losses	$ 6,551	$ 12,935	$ 20,019	$ 27,301
Non Purchased Credit Impaired Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total losses	4,427	12,935	17,895	27,301
Other real estate and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total losses	$ 2,124	$ 0	$ 2,124	$ 0