Stock Option Activity (Details) - Stock Options - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Options Outstanding
Balances (in shares)	402
Granted (in shares)	0		2
Exercised (in shares)	(163)
Forfeited, cancelled or expired (in shares)	(33)
Balances (in shares)	206	402
Options vested and expected to vest (in shares)	206
Options vested (in shares)	198	356	462
Weighted Average Exercise Price
Balances (in dollars per share)	$ 25.42
Granted (in dollars per share)	0.00
Exercised (in dollars per share)	19.81
Forfeited, cancelled or expired (in dollars per share)	42.81
Balances (in dollars per share)	27.08	$ 25.42
Options vested and expected to vest (in dollars per share)	27.07
Options vested (in dollars per share)	$ 26.98
Weighted Average Contractual Term (Years)
Ending balance (in years)	3 years 9 months 18 days
Options vested and expected to vest at end of period (in years)	3 years 9 months 18 days
Options vested at end of period (in years)	3 years 8 months 12 days
Aggregate Intrinsic Value
Ending balance	$ 3,902
Options vested and expected to vest at end of period	3,898
Options vested at end of period	3,776
Weighted average grant-date fair value (in dollars per share)			$ 12.55
Total intrinsic value of options exercised	4,100	$ 6,100	$ 41,500
Net cash proceeds from the exercise of stock options	$ 3,200