Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
Federal	$ 18,864	$ 15,670	$ 12,790
State	3,668	1,985	1,855
Total current tax expense (benefit)	22,532	17,655	14,645
Deferred
Federal	5,901	20,895	5,489
State	4,528	1,940	910
Total deferred tax expense (benefit)	10,429	22,835	6,399
Income tax expense (benefit)	$ 32,961	$ 40,490	$ 21,044