Goodwill and Other Intangible Assets - Finite-Lived Intangible Assets Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Gross Balance of CDI:
Balance, beginning of year	$ 145,212	$ 145,212	$ 125,945
Additions due to acquisitions	0	0	0
Balance, end of year	145,212	145,212	125,945
Accumulated amortization:
Balance, beginning of year	(59,705)	(55,200)	(42,633)
Amortization	4,143	4,505	3,963
Balance, end of year	(63,848)	(59,705)	(46,596)
Net intangible assets	$ 81,364	$ 85,507	$ 79,349