Stock-Based Compensation - Restricted Stock Activity (Details) shares in Thousands	6 Months Ended
	Jun. 30, 2016 $ / shares shares
Shares (in 000's)
Non-vested at beginning of period (in shares) | shares	225
Granted (in shares) | shares	38
Vested (in shares) | shares	(43)
Forfeited (in shares) | shares	(2)
Non-vested at end of period (in shares) | shares	218
Weighted-Average Grant Date Fair Value
Weighted-Average Grant Date Fair Value Non-vested at beginning of period (in dollars per share) | $ / shares	$ 51.31
Granted (in dollars per share) | $ / shares	51.78
Vested (in dollars per share) | $ / shares	46.73
Forfeited (in dollars per share) | $ / shares	56.69
Weighted-Average Grant Date Fair Value Non-vested at end of period (in dollars per share) | $ / shares	$ 52.25