Accumulated Other Comprehensive Income (Loss) - Amounts Reclassified (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Other interest expense	$ (9,589)			$ (13,990)			$ (31,537)	$ (55,889)
Other operating expense	6,182			3,388			15,773	11,339
Total before tax	34,812			18,820			86,452	41,304
Provision for income taxes	9,399			4,489			22,742	10,091
Net income	25,413	$ 19,258	$ 19,039	14,331	$ 18,272	$ (1,390)	63,710	31,213
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Net gain (loss) on sale of securities	(10)						113	(91)
Provision for income taxes	3						(35)	29
Net income	(7)						78	(62)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Provision for income taxes	828			423			2,458	669
Net income	(1,812)			(929)			(5,425)	(1,471)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] | Interest Rate Swap [Member]
Other interest expense	(2,640)			(1,352)			(7,883)	(2,140)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Other operating expense	(125)			(97)			(375)	(292)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Other operating expense	21			21			63	64
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Total before tax	(104)			(76)			(312)	(228)
Provision for income taxes	32			24			97	71
Net income	$ (72)			$ (52)			$ (215)	$ (157)