Fair Value Measurements - Narrative (Details) (USD $)			9 Months Ended			12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Money market funds	Sep. 30, 2013 Money market funds	Sep. 30, 2014 Other mutual funds	Dec. 31, 2013 Other mutual funds	Sep. 30, 2014 Fair Value, Measurements, Recurring	Dec. 31, 2013 Fair Value, Measurements, Recurring	Sep. 30, 2014 Fair Value, Measurements, Recurring Money market funds	Dec. 31, 2013 Fair Value, Measurements, Recurring Money market funds	Sep. 30, 2014 Fair Value, Measurements, Recurring Other mutual funds	Dec. 31, 2013 Fair Value, Measurements, Recurring Other mutual funds
Cash and Cash Equivalents [Line Items]
Assets, Fair Value Disclosure							$ 9,106,000	$ 2,141,000	$ 6,618,000	$ 118,000	$ 2,488,000	$ 2,023,000
Unrealized gains on the investments			0	0	700,000	700,000
Unrealized gains on the investments after-tax	$ 412,000	$ 429,000