Goodwill and Other Intangible Assets - Finite-Lived Intangible Assets Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Gross Balance of CDI:
Balance, beginning of year	$ 125,945	$ 125,945	$ 125,945	$ 125,945	$ 125,945
Additions due to acquisitions	19,267	0	0	19,267	0
Balance, end of year	145,212	125,945	125,945	145,212	125,945
Accumulated amortization:
Balance, beginning of year	(46,596)	(42,633)	(29,824)	(42,633)	(25,388)
Amortization	(4,066)	(3,963)	(4,281)	(8,029)	(8,717)
Balance, end of year	(50,662)	(46,596)	(34,105)	(50,662)	(34,105)
Net intangible assets	$ 94,550	$ 79,349	$ 91,840	$ 94,550	$ 91,840