Equity Narratives (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Oct. 25, 2017	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016
Subsequent Event [Line Items]
Treasury Stock, Shares, Acquired			4,793,635
Treasury Stock, Value, Acquired, Par Value Method			$ 148,800
Treasury Stock Acquired, Average Cost Per Share			$ 31.04
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 219,400	$ 219,400
Purchase of noncontrolling interest		$ 4,600	$ 4,580	$ 1,961
Business Acquisition, Percentage of Voting Interests Acquired		11.00%	11.00%
Subsequent Event [Member]
Subsequent Event [Line Items]
Treasury Stock, Shares, Acquired	390,063
Treasury Stock, Value, Acquired, Par Value Method	$ 13,400
Treasury Stock Acquired, Average Cost Per Share	$ 34.39
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 206,000