Fair Value Measurements - Significant Unobservable Inputs (Level 3) Used in Valuation of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Trust preferred securities $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Significant unobservable inputs (Level 3) used in the valuation of assets and liabilities measured at fair value on a recurring basis
Fair Value	$ 10,401
Valuation Technique	Discounted cash flows
Significant Unobservable Inputs	Default rate
Minimum
Significant unobservable inputs (Level 3) used in the valuation of assets and liabilities measured at fair value on a recurring basis
Range of Inputs	0.00%
Maximum
Significant unobservable inputs (Level 3) used in the valuation of assets and liabilities measured at fair value on a recurring basis
Range of Inputs	100.00%