Parent Corporation Only Financial Statements (Details) - Condensed Statements of Condition - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents		$ 39,161	$ 52,565
Securities available-for-sale		412,034	435,284
Equity securities		11,460
Other assets		30,216	28,275
Total assets		5,462,092	5,108,442
LIABILITIES AND STOCKHOLDERS' EQUITY
Subordinated debentures		128,556	54,699
Stockholders' equity		613,927	565,437
Total liabilities and stockholders' equity		5,462,092	5,108,442
Parent Company [Member]
ASSETS
Cash and cash equivalents		22,071	7,506
Investment in subsidiaries		692,516	614,083
Receivable due from subsidiaries		32,250
Securities available-for-sale		176	779
Equity securities	[1]	607
Other assets		1,282	322
Total assets		748,902	622,690
LIABILITIES AND STOCKHOLDERS' EQUITY
Other liabilities		6,419	2,554
Subordinated debentures		128,556	54,699
Stockholders' equity		613,927	565,437
Total liabilities and stockholders' equity		$ 748,902	$ 622,690

[1] Beginning January 1, 2018, equity securities were reclassified out of investment securities available-for-sale in conjunction with ASU 2016-01.