Fair Value of Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current and Non-Current Investments [Abstract]
Unrealized gain (loss)			$ 51
Balance, beginning of period		419	368
Acquired investments		1,770
Unrealized gain (loss)		436
Balance, end of period		2,625	419
Proceeds from sale of equity investment	405
Carrying value of equity investment	0
Gain on sale of equity investment	405
Components of accumulated other comprehensive income [Abstract]
Cumulative translation adjustment		1,965	1,961	1,936
Unrealized loss on available-for-sale security, net of tax		(398)	(348)	(392)
Accumulated other comprehensive income		1,567	1,613	1,544
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of notes payable (in hundredths)		107.875%	106.125%
Recurring [Member] | Level 1 [Member]
Current and Non-Current Investments [Abstract]
Balance, beginning of period		106	55
Unrealized gain (loss)		(50)	51
Balance, end of period		56	106
Recurring [Member] | Level 2 [Member]
Current and Non-Current Investments [Abstract]
Balance, beginning of period		0	0
Acquired investments		1,530
Unrealized gain (loss)		486	0
Balance, end of period		2,016	0
Recurring [Member] | Level 3 [Member]
Current and Non-Current Investments [Abstract]
Balance, beginning of period		313	313
Acquired investments		240
Unrealized gain (loss)		0	0
Balance, end of period		$ 553	$ 313