Derivative Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Junior subordinated debentures	$ 43,136	$ 44,384
Notional amount	1,481,109	885,469
Short-term Debt, Total	1,021,500	541,500
Derivative instruments	(59,668)	(17,301)
Customer [Member]
Derivative instruments	62,800
Bank [Member]
Derivative instruments	62,800
Customer and Bank [Member]
Derivative instruments	125,600
Cash Flow Hedging [Member]
Amount reclassified from accumulated other comprehensive loss to interest expense	4,700
Amount to be reclassified from the accumulated comprehensive income (loss) into earnings	4,700
Not Designated as Hedging Instrument [Member]
Notional amount	143,600	18,000
Designated as Hedging Instrument [Member]
Notional amount	316,100	326,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Notional amount	1,021,500	541,500
Interest Rate Swap [Member]
Notional amount	316,100	326,000
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Notional amount	80,779	18,000
Derivative instruments	(6,998)	(3,354)
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Notional amount	1,021,500	541,500
Derivative instruments	(25,300)	(8,530)
Floating Rate Junior Subordinated Debentures [Member]
Amount of hedged item	18,000	18,000
Junior subordinated debentures	$ 61,900	$ 61,900