Fair Value Measurements and Disclosures (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Fair value adjustment of marketable securities and deferred compensation plan liability
Net gain on marketable securities		$ 137	$ 388
Fair Value (Level 1) [Member]
Assets and Liabilities Reported at Fair Value
Marketable securities	[1],[2]	$ 13,418		$ 12,882

[1] Based on quoted prices in active markets for identical securities.

[2] The marketable securities are held in a limited rabbi trust.