Goodwill and Other Intangible Assets - Rollforward of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Finite-lived Intangible Assets [Roll Forward]
CDI and CRI Balance, beginning of period	$ 100,550		$ 109,646	$ 109,646	$ 117,573
CDI and CRI Balance, end of period	100,550	$ 100,550	109,646	100,550	109,646
Finite-lived Intangible Assets Acquired	0		0	750	0
Accumulated Amortization, beginning of period	(82,127)		(79,082)	(86,005)	(79,179)
Amortization expense	(2,890)	(2,889)	(3,751)	(8,858)	(11,581)
Accumulated Amortization, end of period	(85,017)	$ (82,127)	(82,833)	(85,017)	(82,833)
Net CDI and CRI, end of period	15,533		26,813	15,533	26,813
Finite Lived Intangible Assets Fully Amortized Portion	$ 0		$ 0	$ 9,846	$ 7,927