Stock Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 02, 2016
Equity, Class of Treasury Stock [Line Items]
Total number of shares repurchased	0	1,424,000	884,000
Dollar amount of shares repurchased		$ 50,021	$ 24,091
Average price paid per share		$ 35.13	$ 27.24
August 2012 Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchases program, authorized amount				$ 50,000
2016 and 2014 Share Repurchase Programs [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, remaining authorized repurchase amount	$ 54,900