Intangible assets Future amortization expense (Tables)

12 Months Ended

Dec. 31, 2017

Future intangible asset amortization expense [Abstract]

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

The estimated aggregate amortization expense for each of the next five years are as follows:

	(Dollars in thousands)
Year	Amortization
2019	$	1,352
2020	1,492
2021	1,600
2022	1,406
2023	1,292
Thereafter	5,970
	$	13,112