Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity
Beginning balance	$ 841,574	$ 735,618	$ 684,928
Merger-related adjustments	0	5,670	0
Total other comprehensive income (loss), net of tax	(7,160)	8,581	7,498
Ending balance	1,085,963	841,574	735,618
Adjustment related to TCJA		300
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity
Beginning balance	5,773	1,197	(1,678)
Gain (loss) recognized in other comprehensive income (loss), net of tax provision (benefit) of $(1,425), $169 and $793, respectively	(5,360)	(659)	1,910
(Gain) loss reclassified from accumulated other comprehensive income (loss) to interest expense, net of tax provision (benefit) of $478, $185 and $(520), respectively (1)	(1,800)	(435)	965
Merger-related adjustments	0	5,670	0
Total other comprehensive income (loss), net of tax	(7,160)	4,576	2,875
Ending balance	(1,387)	5,773	1,197
Gain recognized in other comprehensive income, tax expense (benefit)	(1,425)	169	793
Gain (loss) reclassified from accumulated other comprehensive loss, tax expense (benefit)	$ 478	$ 185	$ (520)