Deposits (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deposits [Line Items]
Non-interest-bearing checking accounts	$ 550,742	$ 571,360
Interest-bearing checking and money market accounts	1,055,416	1,005,519
Savings deposits	306,510	302,022
Retail certificates of deposit less than $250,000	512,746	504,912
Retail certificates of deposit greater than $250,000	66,387	53,843
Total	$ 2,491,801	$ 2,437,656