CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities:
Net income	$ 96,066	$ 44,314
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	37,567	33,158
Amortization of deferred commissions costs	24,275	0
Amortization of debt issuance costs	436	1,487
Stock-based compensation expense	21,640	19,460
Deferred income tax expense, net	4,291	3,434
Bad debt expense	2,857	2,349
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(5,089)	(5,177)
Prepaid expenses and other current assets	(17,655)	(7,887)
Deferred commissions	(29,554)	0
Deposits and other assets	(1,444)	(103)
Accounts payable and other liabilities	(16,619)	605
Deferred revenue	2,546	3,723
Net cash provided by operating activities	119,317	95,363
Investing activities:
Purchases of property and equipment and other assets	(15,851)	(12,674)
Cash paid for acquisitions, net of cash acquired	(340,074)	(45,068)
Net cash used in investing activities	(355,925)	(57,742)
Financing activities:
Payments of long-term debt	0	(35,000)
Repurchase of restricted stock to satisfy tax withholding obligations	(22,394)	(13,456)
Proceeds from exercise of stock options and employee stock purchase plan	14,214	7,683
Net cash used in financing activities	(8,180)	(40,773)
Effect of foreign currency exchange rates on cash and cash equivalents	(397)	567
Net (decrease) in cash and cash equivalents	(245,185)	(2,585)
Cash and cash equivalents at the beginning of period	1,211,463	567,223
Cash and cash equivalents at the end of period	966,278	564,638
Supplemental cash flow disclosures:
Interest paid	381	3,890
Income taxes paid	24,776	26,241
Supplemental non-cash investing and financing activities:
Stock issued in connection with acquisition - ForRent	$ 36,366	$ 0