Goodwill and Other Intangible Assets - Summary of gross carrying amounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Other intangible assets
Gross carrying amount	$ 119,501	$ 119,501	$ 119,501
Accumulated amortization	(72,692)	(59,882)	(69,685)
Net carrying amount	46,809	59,619	49,816
Amortization expense	3,007	3,281
Estimated amortization expense for other intangibles for each of the next five years
Net carrying amount	46,809	$ 59,619	$ 49,816
Estimated amortization expense for other intangibles for each of the next five quarters
June 30, 2020	2,995
September 30, 2020	2,945
December 31, 2020	2,921
March 31, 2021	2,656
June 30, 2021	2,643
Thereafter	$ 32,649
Minimum
Other intangible assets
Estimated useful lives	2 years
Maximum
Other intangible assets
Estimated useful lives	15 years