Share Repurchase Program - Narrative (Details) - USD ($)	Apr. 18, 2017	Apr. 21, 2016	Feb. 09, 2015	Feb. 06, 2014	Oct. 24, 2012
Share Repurchase Program [Abstract]
Stock repurchase program, authorized amount	$ 140,000,000	$ 100,000,000	$ 300,000,000	$ 100,000,000	$ 60,000,000.0