Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Schedule Of Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance			$ (10,536)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(9,973)		(9,973)
Condensed Consolidated Statements Of Comprehensive Income [Abstract]
Net income	23,726	19,314	43,670	38,492
Other comprehensive income (loss):
Foreign currency translation adjustments	1,254	715	245	228
Unrealized gain on investments, net of tax	42	270	318	351
Other	(1)	0	0	25
Comprehensive income	25,021	20,299	44,233	39,096
Parent [Member]
Schedule Of Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income before reclassifications			563
Amounts reclassified from accumulated other comprehensive income			0
Foreign currency translation adjustments [Member]
Schedule Of Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance			(8,681)
Other comprehensive income before reclassifications			245
Amounts reclassified from accumulated other comprehensive income			0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(8,436)		(8,436)
Unrealized loss on investments [Member]
Schedule Of Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance			(1,851)
Other comprehensive income before reclassifications			318
Amounts reclassified from accumulated other comprehensive income			0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(1,533)		(1,533)
Other [Member]
Schedule Of Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance			(4)
Other comprehensive income before reclassifications			0
Amounts reclassified from accumulated other comprehensive income			0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	$ (4)		$ (4)