Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Amount of certificates of deposit and other time deposits of $250,000 or more outstanding
Under 3 months	$ 107,747
4-6 months	75,414
7-12 months	109,311
Over 12 months	261,330
Total	553,802	$ 348,300
Maturities of time deposits, including both private and public funds
2018	612,866
2019	385,988
2020	205,651
2021	45,726
2022	16,415
Thereafter	3,327
Total	$ 1,269,973	$ 1,056,652