Other Intangible Asset - Estimated Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Intangible Assets
Intangibles amortization	$ 11,472	$ 11,401	$ 10,596
Estimated amortization expense for the next five years
2019	10,954
2020	10,932
2021	10,670
2022	10,520
2023	$ 10,520
Weighted average remaining life for intangible assets	10 years 6 months
Amount received from settlement		$ 1,275	$ 10,050