Consolidated Statements of Shareholders' Equity (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Purchase of common stock through tender offer, related costs	$ 140
Tax provision (benefit) on unrealized gain (loss) on investments	(2)	1	10
Treasury Stock [Member]
Purchase of common stock through tender offer, related costs	140
Accumulated Other Comprehensive Income (Loss) [Member]
Tax provision (benefit) on unrealized gain (loss) on investments	$ (2)	$ 1	$ 10