Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the year	$ 760,723	$ 508,305	$ 481,763
Other comprehensive (loss) income	17,833	(6,064)	1,526
ASU Implementation				$ (399)	$ 0	$ 0
Balance at the end of the year	809,311	760,723	508,305
AOCI attributable to parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the year	(7,455)	(1,298)	(2,606)
Other comprehensive income (loss) before reclassification	18,094	(5,956)	1,530
Amounts reclassified from AOCI for gain on sale of investment securities included in net income	(261)	(108)	(4)
Other comprehensive (loss) income	17,833	(6,064)	1,526
ASU Implementation				$ 0	$ (93)	$ (218)
Balance at the end of the year	$ 10,378	$ (7,455)	$ (1,298)