Common and Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	9 Months Ended
	Dec. 01, 2015	Oct. 23, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Equity [Abstract]
Increase in share repurchase authorized amount	$ 300,000
Purchase of common stock (in shares)			222,000	739,000
Repurchase of common stock, including subsequent settlements			$ 23,600	$ 55,000
Remaining authorized repurchase amount			$ 556,400
Common stock, authorized (in shares)			150,000,000		150,000,000
Common stock, par value (in dollars per share)			$ 0.01		$ 0.01
Preferred stock, authorized (in shares)			5,000,000		5,000,000
Preferred stock, par value (in dollars per share)			$ 0.01		$ 0.01
Preferred stock, shares outstanding (in shares)			0		0
Subsequent Event [Line Items]
Purchase of common stock			$ 22,650	$ 57,272
Subsequent Event
Subsequent Event [Line Items]
Purchase of common stock		$ 1,000