Share Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Millions	5 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Jan. 17, 2017
Equity [Abstract]
Authorized amount				$ 200,000,000
Value repurchased	$ 45,300,000	$ 45,349,000	$ 171,547,000
Shares repurchased (in shares)	1.1
Shares repurchased, average cost per share (in dollars per share)	$ 42.04