Stockholders' Equity (Details) $ / shares in Units, $ in Millions									3 Months Ended		9 Months Ended
	Nov. 04, 2016 $ / shares	Sep. 15, 2016 USD ($)	Aug. 08, 2016 $ / shares	Jun. 15, 2016 USD ($)	May 25, 2016	May 09, 2016 $ / shares	Mar. 28, 2016 USD ($)	Feb. 24, 2016 $ / shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) $ / shares shares
Subsequent Event [Line Items]
Stock split					2
Dividends per share (in dollars per share) | $ / shares			$ 0.08			$ 0.08		$ 0.08	$ 0.08	$ 0.07	$ 0.24	$ 0.20
Cash payment amount | $		$ 3.8		$ 3.7			$ 3.8				$ 11.3	$ 9.1
Common stock available for future share repurchases, amount | $									$ 4.3		$ 4.3
Common stock repurchased, number of shares repurchased (in shares) | shares									99,210	99,022	188,126	296,838
Common stock repurchased, average price per share (in dollars per share) | $ / shares									$ 37.77	$ 30.30	$ 38.52	$ 30.32
Common stock repurchased, total repurchase costs | $									$ 3.7	$ 3.0	$ 7.2	$ 9.0
Subsequent Event
Subsequent Event [Line Items]
Dividends per share (in dollars per share) | $ / shares	$ 0.09