Equity - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Oct. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Purchase of treasury stock	$ 1,860	$ 709	$ 1,485	$ 5,877	$ 17,164	$ 3,876
Treasury Stock
Equity, Class of Treasury Stock [Line Items]
Purchase of treasury stock (in shares)	79,592			276,982			193,025	1,110,492
Purchase of treasury stock	$ 1,860	$ 709	$ 1,485	$ 5,877	$ 17,164	$ 3,876	$ 4,100
Class B Shares
Equity, Class of Treasury Stock [Line Items]
Number of shares authorized under share repurchase program (in shares)									4,000,000
Purchase of treasury stock (in shares)							200,000
Remaining number of shares authorized to be repurchased (in shares)	900,000						900,000