CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 107,516	$ 100,027
Other comprehensive income, net of tax:
Net change in unrealized gains on available-for-sale investment securities	12,916	9,318
Foreign currency translation adjustments	(33)	0
Other comprehensive income	12,883	9,318
COMPREHENSIVE INCOME	$ 120,399	$ 109,345