Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Cash and Cash Equivalents [Line Items]
Unrealized gains on the investments after-tax	$ 345	$ 346
Money market funds
Cash and Cash Equivalents [Line Items]
Realized gains on the investments	0
Unrealized gains on the investments	0
Other mutual funds
Cash and Cash Equivalents [Line Items]
Unrealized gains on the investments	600	600
Unrealized gains on the investments after-tax	300	300
Fair Value, Measurements, Recurring
Cash and Cash Equivalents [Line Items]
Assets, Fair Value Disclosure	4,513	2,310
Fair Value, Measurements, Recurring | Money market funds
Cash and Cash Equivalents [Line Items]
Assets, Fair Value Disclosure	2,118	118
Fair Value, Measurements, Recurring | Other mutual funds
Cash and Cash Equivalents [Line Items]
Assets, Fair Value Disclosure	$ 2,395	$ 2,192