Fair Value Measurements (Details 7) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 42,056	$ 544,658
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	25,680	55,952
Non Purchased Credit Impaired Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	41,103	61,095
Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 25,680	$ 55,952
Minimum | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	3.75%
Maximum | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	7.75%
Weighted Average | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	6.81%
Discount Rates | Discounted Cash Flow | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 12,531
Discount Rates | Weighted Average | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	6.81%
No Discounts | Internal enterprise value methodology | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 6,819
No Discounts | Third party appraisals | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 6,330