CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Balance at Dec. 31, 2010	$ 381,502	$ 208	$ 374,981	$ (8,706)	$ 15,019
Balance (in shares) at Dec. 31, 2010		20,773,000
Net income	14,656				14,656
Foreign currency translation adjustment	25			25
Net change in unrealized gain (loss) on investments	113			113
Exercise of stock options (in shares)		198,000
Exercise of stock options	6,214	2	6,212
Restricted stock grants (in shares)		197,000
Restricted stock grants	1	1	0
Restricted stock grants surrendered (in shares)		(63,000)
Restricted stock grants surrendered	(2,307)		(2,307)
Stock compensation expense, net of forfeitures	8,056		8,056
Stock issued for equity offering (in shares)		4,313,000
Stock issued for equity offering	247,924	43	247,881
Employee stock purchase plan (in shares)		8,000
Employee stock purchase plan	452		452
Excess tax benefit from stock-based compensation	2,541		2,541
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 change in unrealized gain (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)		(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, Inc. (in shares)		1,880,000
Consideration for LoopNet, Inc.	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 change in unrealized gain (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)		(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