Consolidated Statements Of Changes In Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Beginning balance, value at Dec. 31, 2009		$ 79	$ 387,885	$ (18,996)	$ 809,077	$ 1,178,045
Beginning balance, shares at Dec. 31, 2009		78,559,350
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income					81,817	81,817
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation				(6,704)		(6,704)
Grant of restricted stock units			950			950
Restricted stock grant and expense, net of forefeitures, value			11,367			11,367
Restricted stock grant and expense, net of forefeitures, shares		342,694
Exercise of stock options, value			927			927
Exercise of stock options, shares		87,150				87,150
Tax benefit (expense) from exercise of stock options			560			560
Stock options compensation expense			15,493			15,493
Shares issued under Employee Stock Purchase Plan, value			2,233			2,233
Shares issued under Employee Stock Purchase Plan, shares		94,250
Shares withheld and retired, value			(4,137)			(4,137)
Exercise of stock options, shares		(132,391)
Ending balance, value at Dec. 31, 2010		79	415,278	(25,700)	890,894	1,280,551
Ending balance, shares at Dec. 31, 2010		78,951,053
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income					142,554	142,554
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation				(1,236)		(1,236)
Grant of restricted stock units			1,140			1,140
Restricted stock grant and expense, net of forefeitures, value			5,996			5,996
Restricted stock grant and expense, net of forefeitures, shares		541,425
Exercise of stock options, value		1	10,262			10,263
Exercise of stock options, shares		876,435				876,435
Tax benefit (expense) from exercise of stock options			9,004			9,004
Stock options compensation expense			3,348			3,348
Shares issued to pay performance share unit, value			2,759			2,759
Shares issued to pay performance share unit, shares		67,288
Shares issued under Employee Stock Purchase Plan, value			2,594			2,594
Shares issued under Employee Stock Purchase Plan, shares		75,745
Share issuance cost			(335)			(335)
Shares withheld and retired, value			(3,039)			(3,039)
Exercise of stock options, shares		(86,503)
Ending balance, value at Dec. 31, 2011		80	447,007	(26,936)	1,033,448	1,453,599
Ending balance, shares at Dec. 31, 2011		80,425,443
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income					365,935	365,935
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized net gain (loss) on investment securities				(897)		(897)
Foreign currency translation				8,516		8,516
Grant of restricted stock units			1,927			1,927
Restricted stock grant and expense, net of forefeitures, value			16,981			16,981
Restricted stock grant and expense, net of forefeitures, shares		295,366
Vesting of restricted stock assumed with acquisition		64,356
Exercise of stock options, value		2	14,775			14,777
Exercise of stock options, shares		1,962,248				1,962,248
Tax benefit (expense) from exercise of stock options			(675)			(675)
Stock options compensation expense			4,829			4,829
Shares issued to pay performance share unit, value			1,140			1,140
Shares issued to pay performance share unit, shares		43,259
Shares issued under Employee Stock Purchase Plan, value			3,360			3,360
Shares issued under Employee Stock Purchase Plan, shares		147,026
Stock issued under acquisition, value		74,699,065	2,361,391			2,361,467
Stock issued under acquisition, shares		76
Fair value of options exchanged in with acquisition			3,932			3,932
Share issuance cost			(388)			(388)
Shares withheld and retired, value			(3,424)			(3,424)
Exercise of stock options, shares		(135,128)
Ending balance, value at Dec. 31, 2012		$ 158	$ 2,850,855	$ (19,317)	$ 1,399,383	$ 4,231,079
Ending balance, shares at Dec. 31, 2012		157,501,635