Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tax Credit Carryforward [Line Items]
Provisional income tax expense for impact of remeasurement of deferred tax asset		$ 38,200,000
Increase in deferred tax asset due to merger and acquisition	$ 2,640,000
Federal alternative minimum tax credits	1,280,000
Valuation allowance	3,371,000	4,414,000
Net deferred tax asset	64,224,000	88,049,000
Tax benefit related to uncertain tax positions that increases income from continuing operations	2,840,000
Penalties and interest related to income taxes	0	0	$ 0
Accrued penalties and interest	0	$ 0
Begin to expire in 2019 | State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	3,710,000
State tax credits	5,170,000
Begin to expire in 2021 | State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	10,500,000
Begin to expire in 2030 | State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	320,000,000
Begin to expire in 2027 | Federal
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	$ 98,000,000