Income Taxes Income Taxes (Tables)

6 Months Ended

Jun. 30, 2018

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

The following table presents the provision for income taxes and the effective tax rates for the periods indicated.

	Three Months Ended June 30,						Six Months Ended June 30,
(Dollars in thousands)	2018			2017			2018			2017
Income before income tax expense	$	105,581		$	80,051		$	186,754		$	153,043
Income tax expense	30,457			28,033			48,009			50,552
Effective tax rate	28.8		%	35.0		%	25.7		%	33.0		%