Common Stock and Treasury Stock - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Common Stock [Line Items]
Share repurchase program, authorized amount	$ 75,800,000		$ 75,800,000
Stock repurchase program, remaining authorization amount	$ 19,200,000		$ 19,200,000
Stock Buy back Program [Member]
Common Stock [Line Items]
Stock Repurchased During Period, Shares	800	8,600	1,600	11,100
Stock Repurchased During Period, Value	$ 21,000	$ 247,000	$ 41,000	$ 327,000