Accumulated Other Comprehensive Loss - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Summary of changes in accumulated other comprehensive loss
Beginning Balance	$ 530,320	$ 581,196	$ 533,111	$ 592,584
Total other comprehensive (loss) income, net of tax	(2)	219	604	848
Ending Balance	542,140	549,540	542,140	549,540
Unrealized (loss) gain on available for sale securities
Summary of changes in accumulated other comprehensive loss
Beginning Balance			(674)
Other comprehensive loss before reclassifications			602
Amounts reclassified from accumulated other comprehensive loss			2
Total other comprehensive (loss) income, net of tax	(2)	$ 219	604	$ 848
Ending Balance	$ (70)		$ (70)