Goodwill and Other Intangible Assets - Goodwill Roll Forward (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021
Goodwill [Roll Forward]
Balance, beginning of year	$ 898,569	$ 808,322	$ 901,166
Goodwill acquired during the year	0	92,844
Purchase accounting adjustments	2,743	0
Balance, end of year	901,312	901,166	901,312
Accumulated impairment losses at end of year	$ 0	$ 0	$ 0