Shareholders' Equity (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	May 08, 2019	Mar. 31, 2019	Mar. 31, 2018	Mar. 22, 2019	Aug. 07, 2018	Aug. 31, 2017
Stock Repurchase Program [Abstract]
Stock repurchase program, shares authorized (in shares)						2,464,209
Stock repurchase program, authorized amount				$ 3,500
Repurchase of common shares amount paid	$ 3,031	$ 468	$ 235
Maximum [Member]
Stock Repurchase Program [Abstract]
Stock repurchase program, authorized amount					$ 25,000
Class A [Member]
Stock Repurchase Program [Abstract]
Repurchase of common stock (in shares)		100
Class A [Member] | Subsequent Event [Member]
Stock Repurchase Program [Abstract]
Repurchase of common stock (in shares)	23
Class B [Member]
Stock Repurchase Program [Abstract]
Repurchase of common stock (in shares)		24,858
Class B [Member] | Subsequent Event [Member]
Stock Repurchase Program [Abstract]
Repurchase of common stock (in shares)	172,416