CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ 375,446	$ (38,453)	$ (62,813)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	75,598	60,961	37,279
Non-cash interest and other expense	34,547	31,257	14,421
Loss on extinguishment of long-term debt	0	5,047	0
Non-cash lease expense	29,696	0	0
Share-based compensation	297,863	216,881	155,836
Replacement stock awards issued in connection with acquisition	0	899	0
Gain on sale of asset group	(373,445)	0	0
Loss (gain) on revaluation of equity investment	12,326	(20,342)	0
Recovery of common stock in connection with indemnification settlement agreement	(1,069)	(2,745)	0
Transaction and loan losses	126,959	88,077	67,018
Change in deferred income taxes	(1,376)	(646)	(1,385)
Changes in operating assets and liabilities:
Settlements receivable	(248,271)	245,795	(305,831)
Customer funds	(204,208)	(131,004)	(59,468)
Purchase of loans held for sale	(2,266,738)	(1,609,611)	(1,184,630)
Sales and principal payments of loans held for sale	2,168,682	1,579,834	1,145,314
Customers payable	523,795	15,597	301,778
Settlements payable	41,697	(60,651)	63,637
Charge-offs to accrued transaction losses	(78,325)	(58,192)	(46,148)
Other assets and liabilities	(47,478)	(27,624)	2,703
Net cash provided by operating activities	465,699	295,080	127,711
Cash flows from investing activities:
Purchase of marketable debt securities	(992,583)	(1,000,346)	(544,910)
Proceeds from maturities of marketable debt securities	430,888	197,454	168,224
Proceeds from sale of marketable debt securities	548,619	171,992	89,087
Purchase of marketable debt securities from customer funds	(311,499)	(148,096)	0
Proceeds from maturities of marketable debt securities from customer funds	158,055	0	0
Proceeds from sale of marketable debt securities from customer funds	17,493	48,334	0
Purchase of property and equipment	(62,498)	(61,203)	(26,097)
Purchase of other investments	(15,250)	0	(25,000)
Proceeds from sale of equity investment	33,016	0	0
Purchase of intangible assets	0	(1,584)	0
Proceeds from sale of asset group	309,324	0	0
Business combinations, net of cash acquired	(20,372)	(112,399)	(1,915)
Net cash provided by (used in) investing activities:	95,193	(905,848)	(340,611)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net	0	855,663	428,250
Purchase of convertible senior note hedges	0	(172,586)	(92,136)
Proceeds from issuance of warrants	0	112,125	57,244
Principal payment on conversion of senior notes	0	(219,384)	0
Payment for termination of Starbucks warrant	0	0	(54,808)
Proceeds from the exercise of stock options and purchases under the employee stock purchase plan, net	118,514	133,850	162,504
Payments for tax withholding related to vesting of restricted stock units	(212,264)	(189,124)	(44,682)
Other financing activities	(5,124)	(4,789)	(1,439)
Net cash provided by (used in) financing activities	(98,874)	515,755	454,933
Effect of foreign exchange rate on cash and cash equivalents	3,841	(7,221)	4,303
Net increase (decrease) in cash, cash equivalents and restricted cash	465,859	(102,234)	246,336
Cash, cash equivalents and restricted cash, beginning of the year	632,847	735,081	488,745
Cash, cash equivalents and restricted cash, end of the year	$ 1,098,706	$ 632,847	$ 735,081