Goodwill and Other Intangible Assets (Summary of the Gross Carrying Amount and Accumulated Amortization of Intangible Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Amortizable intangible assets:
Gross Carrying Amount	$ 45,024	$ 43,532
Accumulated Amortization	30,507	26,315
Unamortizable intangible assets:
Goodwill	240,972	234,368
Customer lists
Amortizable intangible assets:
Gross Carrying Amount	6,013	6,013
Accumulated Amortization	2,575	2,185
Core deposit intangibles
Amortizable intangible assets:
Gross Carrying Amount	28,440	28,440
Accumulated Amortization	23,112	20,610
SBA servicing asset
Amortizable intangible assets:
Gross Carrying Amount	9,268	7,776
Accumulated Amortization	3,624	2,393
Other
Amortizable intangible assets:
Gross Carrying Amount	1,303	1,303
Accumulated Amortization	$ 1,196	$ 1,127