Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018	Jan. 01, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the year	$ 508,305	$ 481,763	$ 469,970
Other comprehensive (loss) income	(6,064)	1,526	(5,165)
ASU Implementation				$ 0	$ 0
Balance at the end of the year	760,723	508,305	481,763
AOCI attributable to parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the year	(1,298)	(2,606)	2,559
Other comprehensive (loss) income before reclassification	(5,956)	1,530	(4,311)
Amounts reclassified from AOCI for gain on sale of investment securities included in net income	(108)	(4)	(854)
Other comprehensive (loss) income	(6,064)	1,526	(5,165)
ASU Implementation	(93)	(218)	0	$ (93)	$ (218)
Balance at the end of the year	$ (7,455)	$ (1,298)	$ (2,606)