Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-lived Intangible Assets [Roll Forward]
Balance at the beginning of the year, gross	$ 97,976	$ 58,959	$ 48,550
Balance at the beginning of the year, accumulated amortization	40,827	32,962	28,280
Balance at the beginning of the year, net	57,149	25,997	20,270
Additions	12,230	39,017	10,409
Amortization expense	(7,444)	(7,865)	(4,682)
Balance at the end of the year, gross	110,206	97,976	58,959
Balance at the end of the year, accumulated amortization	48,271	40,827	32,962
Balance at the end of the year, net	$ 61,935	$ 57,149	$ 25,997
Weighted-average remaining life (in years)	7 years 10 months	8 years 4 months	7 years 6 months 20 days
Minimum
Finite-lived Intangible Assets [Roll Forward]
Estimated useful lives (in years)	8 months	2 months	7 months
Maximum
Finite-lived Intangible Assets [Roll Forward]
Estimated useful lives (in years)	9 years 10 months	9 years 3 months	9 years 3 months