Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Banking and Thrift [Abstract]
Noninterest bearing demand, balance	$ 1,982,912	$ 1,775,684	$ 1,405,067
Interest bearing transaction, balance	$ 420,417	$ 289,122	$ 178,797
Interest bearing transaction	0.46%	0.16%	0.16%
Savings and money market, balance	$ 2,621,146	$ 2,902,560	$ 2,835,325
Savings and money market	0.70%	0.54%	0.34%
Time, $100,000 or more, balance	$ 515,682	$ 464,842	$ 406,570
Time, $100,000 or more	1.20%	0.95%	0.77%
Other time, balance	$ 313,827	$ 283,906	$ 332,685
Other time	1.17%	0.86%	0.74%
Total, balance	$ 5,853,984	$ 5,716,114	$ 5,158,444