Fair Value Measurements Schedule Of Fair Value Of Assets (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Mutual funds and money market funds, fair value	$ 386,000		$ 3,486,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member]
Assets measured at fair value	65,337,000		36,242,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Money Market Funds [Member] | Cash and cash equivalents [Member] | Fair Value, Measurements, Recurring [Member]
Money market funds, included in cash and cash equivalents, fair value	50,001,000		20,001,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Money Market Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	2,135,000	[1]	4,357,000	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Mutual Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	13,201,000	[1]	11,884,000	[1]
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets measured at fair value	13,201,000		11,884,000
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member] | Cash and cash equivalents [Member] | Fair Value, Measurements, Recurring [Member]
Money market funds, included in cash and cash equivalents, fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	0	[1]	0	[1]
Fair Value, Inputs, Level 1 [Member] | Mutual Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	13,201,000	[1]	11,884,000	[1]
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets measured at fair value	52,136,000		24,358,000
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member] | Cash and cash equivalents [Member] | Fair Value, Measurements, Recurring [Member]
Money market funds, included in cash and cash equivalents, fair value	50,001,000		20,001,000
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	2,135,000	[1]	4,357,000	[1]
Fair Value, Inputs, Level 2 [Member] | Mutual Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	0	[1]	0	[1]
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets measured at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member] | Cash and cash equivalents [Member] | Fair Value, Measurements, Recurring [Member]
Money market funds, included in cash and cash equivalents, fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	0	[1]	0	[1]
Fair Value, Inputs, Level 3 [Member] | Mutual Funds [Member] | Investments, employee benefit plans, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Mutual funds and money market funds, fair value	$ 0	[1]	$ 0	[1]

[1] Included in Investments, employee benefit plans fair value on the consolidated balance sheets.