Share Repurchases (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Jul. 31, 2016
Equity [Abstract]
Maximum stock repurchase program amount			$ 200,000,000
Stock repurchased during period (in shares)	0.9	1.8
Average price per share of stock repurchased (usd per share)	$ 22.06	$ 24.89
Remaining repurchase authorization	$ 155,000,000	$ 155,000,000