Treasury Stock (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Apr. 26, 2017
Class of Stock [Line Items]
Shares available for repurchase (in shares)	194,565
Shares repurchased (in shares)	185,000	33,000
Cost of shares repurchased	$ 11,389	$ 1,724
Subsequent event
Class of Stock [Line Items]
Shares available for repurchase (in shares)			200,000
Increase in shares available for repurchase (in shares)			5,435