CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings
Balance at Dec. 31, 2011	$ 659,177	$ 254	$ 637,816	$ (8,568)	$ 29,675
Balance (in shares) at Dec. 31, 2011		25,426,000
Net income	9,915				9,915
Foreign currency translation adjustment	1,277			1,277
Net decrease in unrealized loss on investments	773			773
Exercise of stock options (in shares)		273,000
Exercise of stock options	9,196	2	9,194
Restricted stock grants (in shares)		855,000
Restricted stock grants	0	8	(8)
Restricted stock grants surrendered (in shares)		(96,000)
Restricted stock grants surrendered	(4,204)	0	(4,204)
Stock compensation expense, net of forfeitures	12,207		12,207
Employee stock purchase plan (in shares)		10,000
Employee stock purchase plan	749		749
Consideration for LoopNet (in shares)		1,880,000
Consideration for LoopNet	137,055	19	137,036
Excess tax benefit from stock-based compensation	198		198
Balance at Dec. 31, 2012	826,343	283	792,988	(6,518)	39,590
Balance (in shares) at Dec. 31, 2012		28,348,000
Net income	29,734				29,734
Foreign currency translation adjustment	610			610
Net decrease in unrealized loss on investments	378			378
Exercise of stock options (in shares)		409,000
Exercise of stock options	16,823	3	16,820
Restricted stock grants (in shares)		238,000
Restricted stock grants	0	2	(2)
Restricted stock grants surrendered (in shares)		(158,000)
Restricted stock grants surrendered	(8,469)	0	(8,469)
Stock compensation expense, net of forfeitures	41,403		41,403
Employee stock purchase plan (in shares)		11,000
Employee stock purchase plan	1,455		1,455
Excess tax benefit from stock-based compensation	19,585		19,585
Balance at Dec. 31, 2013	927,862	288	863,780	(5,530)	69,324
Balance (in shares) at Dec. 31, 2013		28,848,000
Net income	44,869				44,869
Foreign currency translation adjustment	(1,690)			(1,690)
Net decrease in unrealized loss on investments	836			836
Exercise of stock options (in shares)		68,000
Exercise of stock options	3,803	1	3,802
Restricted stock grants (in shares)		260,000
Restricted stock grants	0	2	(2)
Restricted stock grants surrendered (in shares)		(321,000)
Restricted stock grants surrendered	(50,555)	(2)	(50,553)
Stock compensation expense, net of forfeitures	28,503		28,503
Stock issued for equity offering (in shares)		3,450,000
Stock issued for equity offering	529,360	34	529,326
Employee stock purchase plan (in shares)		13,000
Employee stock purchase plan	2,152		2,152
Excess tax benefit from stock-based compensation	28,406		28,406
Balance at Dec. 31, 2014	$ 1,513,546	$ 323	$ 1,405,414	$ (6,384)	$ 114,193
Balance (in shares) at Dec. 31, 2014		32,318,000