Shareholders' Equity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Stock Repurchase Program [Abstract]
Stock repurchase program, shares authorized (in shares)	2,464,209
Stock repurchase program, authorized amount	$ 25,000
Stock repurchase program, authorized amount per quarter	6,250
Repurchase of common shares	$ 10,283	$ 2,620
Class A [Member]
Stock Repurchase Program [Abstract]
Repurchase of common stock (in shares)	6,520
Class B [Member]
Stock Repurchase Program [Abstract]
Repurchase of common stock (in shares)	595,326
Rule 10b5-1 [Member]
Stock Repurchase Program [Abstract]
Stock repurchase program, authorized amount	$ 625