Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Summary of Deposits
Noninterest-bearing demand	$ 3,809,252	$ 3,725,779
Savings and money market accounts	4,092,082	3,655,671
Interest-bearing demand	3,316,278	2,724,415
Brokered deposits	985,522	453,227
Other time deposits	3,390,148	3,083,711
Total deposits	15,593,282	13,642,803
Demand deposit overdrafts	7,900	5,900
Time Deposits, $250,000 or More	2,100,000	$ 1,600,000
Maturities of Time Deposits
2019	2,776,097
2020	1,032,314
2021	148,995
2022	82,076
2023	33,900
Thereafter	866
Total	4,074,248
Executive officers, directors, principal shareholders and related interests
Summary of Deposits
Total deposits	$ 9,800