Equity Incentive Plans (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Summary of the activity of stock option awards
Options outstanding, Beginning Balance, Shares	849
Options outstanding, Beginning Balance, Wtd. Avg. Exercise Price	$ 19.67
Options outstanding, Beginning Balance, Wtd. Avg., Remaining Contractual Term	6 years 10 months 28 days	6 years 4 months 21 days
Options outstanding, Beginning Balance, Aggregate Intrinsic Value	$ 10,654
Options granted, Shares	227
Options granted, Wtd. Avg. Exercise Price	$ 32.41
Options exercised, Shares	(338)
Options exercised, Wtd. Avg. Exercise Price	$ 19.34
Options forfeited/canceled/expired, Shares	(24)
Options forfeited/canceled/expired, Wtd. Avg. Exercise Price	$ 26.27
Options outstanding, Ending Balance, Shares	714	849
Options outstanding, Ending Balance, Wtd. Avg. Exercise Price	$ 23.64	$ 19.67
Options outstanding, Ending Balance, Wtd. Avg., Remaining Contractual Term	6 years 10 months 28 days	6 years 4 months 21 days
Options outstanding, Ending Balance, Aggregate Intrinsic Value	10,425	10,654
Options vested and expected to vest at September 30, 2014, Shares	683
Options vested and expected to vest at September 30, 2014, Wtd. Avg. Exercise Price	$ 23.36
Options vested and expected to vest at September 30, 2014, Wtd. Avg., Remaining Contractual Term	6 years 9 months 26 days
Options vested and expected to vest at September 30, 2014, Aggregate Intrinsic Value	10,146
Options exercisable at September 30, 2014 Shares	410
Options exercisable at September 30, 2014, Wtd. Avg. Exercise Price	$ 20.64
Options exercisable at September 30, 2014, Wtd. Avg. Remaining Contractual Term	5 years 10 months 21 days
Options exercisable at September 30, 2014, Aggregate Intrinsic Value	$ 7,200