Derivative Financial Instruments Interest rate swaps designated as cash flow hedges (Details) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) contract	Jun. 30, 2019	Dec. 31, 2019 USD ($)
Derivative [Line Items]
Weighted average pay rates	2.18%		2.18%
Weighted average receive rates	0.58%		1.73%
Weighted average maturity	5 years 1 month 6 days	5 years 4 months 24 days
Pre-tax unrealized losses included in AOCI	$ (13,233)		$ (3,503)
Maximum Length of Time Hedged in Interest Rate Cash Flow Hedge	10 years
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 160,000		$ 160,000
Derivative, Number of Instruments Held | contract	17