Stock Repurchase Plan - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Oct. 31, 2015
Equity Class Of Treasury Stock [Line Items]
Total cost of shares repurchased	$ 84,900,000	$ 100,000,000
2015 Repurchase Plan
Equity Class Of Treasury Stock [Line Items]
Authorized amount of outstanding common stock to be repurchased			$ 250,000,000
Total cost of shares repurchased	84,900,000
Remaining amount of authorized under 2015 Repurchase Plan	$ 119,000,000