Stock-Based Compensation (RSU Activity) (Details) - USD ($)	1 Months Ended	9 Months Ended
	Apr. 30, 2016	Sep. 30, 2016
RSUs
Number of Shares
Balance at the beginning of the period (in shares)		682,000
Granted (in shares)		586,000
Vested (in shares)		(301,000)
Cancelled (in shares)		(73,000)
Balance at the end of the period (in shares)		894,000
Weighted-Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)		$ 30.18
Granted (in dollars per share)		27.46
Vested (in dollars per share)		30.10
Cancelled (in dollars per share)		29.24
Balance at the end of the period (in dollars per share)		$ 28.50
RSUs | Performance-Based Vesting
Number of Shares
Balance at the beginning of the period (in shares)		6,000
Granted (in shares)	11,720	12,000
Vested (in shares)		(6,000)
Balance at the end of the period (in shares)		12,000
Weighted-Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)		$ 27.21
Granted (in dollars per share)	$ 28.09	28.09
Vested (in dollars per share)		27.21
Balance at the end of the period (in dollars per share)		$ 28.09
Additional Disclosure
Grant-date fair value (in dollars)	$ 329,000
Restricted Stock | Outside directors
Number of Shares
Granted (in shares)		5,245
Weighted-Average Grant Date Fair Value
Granted (in dollars per share)		$ 28.56
Additional Disclosure
Grant-date fair value (in dollars)		$ 150,000