Deposits - Maturity Distribution of Time Certificates of Deposits (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Maturity distribution of time certificates of deposit
Three months or less	$ 431,455
Over three through six months	474,541
Over six through twelve months	563,093
One to two years	207,881
Two to three years	94,555
Three to four years	50,960
Four to five years	57,015
Thereafter	750
Total	1,880,250
Under $250,000
Maturity distribution of time certificates of deposit
Three months or less	193,946
Over three through six months	212,514
Over six through twelve months	347,878
One to two years	90,481
Two to three years	80,378
Three to four years	35,555
Four to five years	45,201
Thereafter	500
Total	1,006,453
$250,000 or More
Maturity distribution of time certificates of deposit
Three months or less	237,509
Over three through six months	262,027
Over six through twelve months	215,215
One to two years	117,400
Two to three years	14,177
Three to four years	15,405
Four to five years	11,814
Thereafter	250
Total	$ 873,797