Equity Incentive Plans (Options Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Summary of the activity of stock option awards
Options outstanding, Beginning Balance , Shares	849,000
Options granted, shares	227,000	0
Options exercised, Shares	(386,000)
Options forfeited/canceled/expired, Shares	(26,000)
Options outstanding, Ending Balance , Shares	664,000	849,000
Options vested and expected to vest, Shares	638,000
Options exercisable, Shares				363,000
Options outstanding, Beginning Balance, Wtd. Avg. Exercise Price	$ 19.67
Options granted, Wtd. Avg. Exercise Price	$ 32.41
Options exercised, Wtd. Avg. Exercise Price	$ 19.33
Options forfeited/canceled/expired, Wtd. Avg. Exercise Price	$ 27.00
Options outstanding, Ending Balance, Wtd. Avg. Exercise Price	$ 23.89	$ 19.67
Options vested and expected to vest, Wtd. Average Exercise Price	$ 23.65
Options exercisable, Wtd. Avg. Exercise Price				$ 20.82
Options outstanding, Ending Balance, Wtd. Avg. Remaining Contractual Term	6 years 9 months 7 days	6 years 4 months 21 days
Options vested and expected to vest, Wtd. Avg Remaining Contractual Term	6 years 8 months 9 days
Options exercisable, Wtd. Avg. Remaining Contractual Term	5 years 8 months 27 days
Options outstanding, Beginning Balance, Average Intrinsic Value	$ 10,935	$ 10,654
Options vested and expected to vest, Aggregate Intrinsic Value	10,661
Options exercisable, Aggregate Intrinsic Value				7,095
Intrinsic value of options exercised	5,736	5,564	7,051
Fair value of shares vested	$ 1,095	$ 1,679	$ 2,062