Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income taxes currently payable	$ 17,282	$ 5,638	$ 40,356	$ 31,335
Deferred income taxes	5,993	5,264	10,933	7,316
Provision for income taxes	$ 23,275	$ 10,902	$ 51,289	$ 38,651

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration