Equity Incentive Plans (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Summary of the activity of stock option awards
Options outstanding, Beginning Balance, Shares	664
Options outstanding, Beginning Balance, Wtd. Avg. Exercise Price	$ 23.89
Options outstanding, Beginning Balance, Wtd. Avg., Remaining Contractual Term	7 years 6 months 4 days	6 years 9 months 7 days
Options outstanding, Beginning Balance, Aggregate Intrinsic Value	$ 10,935
Options granted, Shares	256
Options granted, Wtd. Avg. Exercise Price	$ 43.15
Options exercised, Shares	(53)
Options exercised, Wtd. Avg. Exercise Price	$ 23.98
Options forfeited/canceled/expired, Shares	(5)
Options forfeited/canceled/expired, Wtd. Avg. Exercise Price	$ 40.32
Options outstanding, Ending Balance, Shares	862	664
Options outstanding, Ending Balance, Wtd. Avg. Exercise Price	$ 29.53	$ 23.89
Options outstanding, Ending Balance, Wtd. Avg., Remaining Contractual Term	7 years 6 months 4 days	6 years 9 months 7 days
Options outstanding, Ending Balance, Aggregate Intrinsic Value	8,732	10,935
Options vested and expected to vest at March 31, 2015, Shares	806
Options vested and expected to vest at March 31, 2015, Wtd. Avg. Exercise Price	$ 28.92
Options vested and expected to vest at March 31, 2015, Wtd. Avg., Remaining Contractual Term	7 years 4 months 13 days
Options vested and expected to vest at March 31, 2015, Aggregate Intrinsic Value	8,576
Options exercisable at March 31, 2015, Shares	490
Options exercisable at March 31, 2015, Wtd. Avg. Exercise Price	$ 23.84
Options exercisable at March 31, 2015, Wtd. Avg. Remaining Contractual Term	6 years 2 months 12 days
Options exercisable at March 31, 2015, Aggregate Intrinsic Value	$ 7,297