Fair Value Measurements - Recurring and Nonrecurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Measurements, Recurring
Fair value information related to assets
Assets	$ 15,199	$ 11,054
Liabilities	(988)	(1,210)
Fair Value, Measurements, Recurring | Money market funds
Fair value information related to assets
Assets	12,619	8,518
Fair Value, Measurements, Recurring | Other mutual funds
Fair value information related to assets
Assets	2,580	2,536
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1)
Fair value information related to assets
Assets	15,199	11,054
Liabilities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Money market funds
Fair value information related to assets
Assets	12,619	8,518
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Other mutual funds
Fair value information related to assets
Assets	2,580	2,536
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair value information related to assets
Assets	0	0
Liabilities	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Money market funds
Fair value information related to assets
Assets	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other mutual funds
Fair value information related to assets
Assets	0	0
Fair Value, Measurements, Recurring | Significant Unobserved Inputs (Level 3)
Fair value information related to assets
Assets	0	0
Liabilities	(988)	(1,210)
Fair Value, Measurements, Recurring | Significant Unobserved Inputs (Level 3) | Money market funds
Fair value information related to assets
Assets	0	0
Fair Value, Measurements, Recurring | Significant Unobserved Inputs (Level 3) | Other mutual funds
Fair value information related to assets
Assets	0	0
Earnout contingent consideration liability
Fair value information related to assets
Liabilities		(1,210)
Earnout contingent consideration liability | Fair Value, Measurements, Recurring
Fair value information related to assets
Liabilities	(988)
Earnout contingent consideration liability | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1)
Fair value information related to assets
Liabilities	0	0
Earnout contingent consideration liability | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair value information related to assets
Liabilities	0	0
Earnout contingent consideration liability | Fair Value, Measurements, Recurring | Significant Unobserved Inputs (Level 3)
Fair value information related to assets
Liabilities	$ (988)	$ (1,210)