Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net cash flows from operating activities:
Net income	$ 252,847	$ 194,321	$ 252,111
Adjustments to reconcile net income to net cash provided by (used for) operations:
Deferred income tax provision	712,055	118,631	134,016
Depreciation and amortization of property, equipment and leasehold improvements	146,179	144,116	164,067
Other amortization	17,860	22,673	8,006
Share-based compensation	48,384	33,597	74,087
Provision for doubtful accounts	45,868	34,252	20,168
Net securities gains	(23,028)	(29,542)	(62,957)
Income related to associated companies	(34,494)	(171,782)	(185,998)
Distributions from associated companies	143,286	191,455	223,658
Net losses related to property and equipment, and other assets	31,670	83,053	29,776
Gain on sale of subsidiaries	(179,605)	0	0
Gain on disposal of discontinued operations	0	0	(7,836)
Change in estimated litigation reserve	0	0	(96,500)
Net change in:
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	280,703	(107,771)	2,691,028
Trading assets	(596,780)	2,687,399	1,380,230
Investments in managed funds	(52,897)	75,144	(295,342)
Securities borrowed	50,660	(805,779)	(127,060)
Securities purchased under agreements to resell	234,740	(112,777)	56,377
Receivables from brokers, dealers and clearing organizations	(555,109)	(488,623)	551,021
Receivables from customers of securities operations	(732,344)	340,690	58,233
Other receivables	(248,217)	(162,748)	(145,634)
Other assets	2,987	(283,234)	83,414
Trading liabilities	(25,663)	1,727,698	(2,011,277)
Securities loaned	381	(122,946)	420,929
Securities sold under agreements to repurchase	1,838,793	(3,144,433)	(688,355)
Payables to brokers, dealers and clearing organizations	(1,079,516)	569,246	486,841
Payables to customers of securities operations	366,721	(483,188)	(3,455,080)
Trade payables, expense accruals and other liabilities	427,115	361,295	(225,711)
Other	236	(61,900)	(93,967)
Net cash provided by (used for) operating activities	1,072,832	608,847	(761,755)
Net cash flows from investing activities:
Acquisitions of property, equipment and leasehold improvements, and other assets	(193,473)	(318,678)	(295,894)
Proceeds from disposals of property and equipment, and other assets	30,833	62,463	22,820
Proceeds from sale of subsidiary, net of expenses and cash of operations sold	289,767	0	0
Proceeds from disposal of discontinued operations, net of expenses and cash of operations sold	0	0	5,842
Acquisitions, net of cash acquired	0	(9,673)	0
Advances on notes, loans and other receivables	(39,953)	(342,281)	(420,219)
Collections on notes, loans and other receivables	270,689	121,825	153,004
Loans to and investments in associated companies	(3,305,791)	(763,528)	(1,492,060)
Capital distributions and loan repayment from associated companies	3,106,423	703,108	1,389,262
Proceeds from sale of associated companies	173,105	0	0
Deconsolidation of subsidiary entities	(21,129)	(326)	(16,512)
Purchases of investments (other than short-term)	(1,146,595)	(739,298)	(873,831)
Proceeds from maturities of investments	344,223	162,393	379,629
Proceeds from sales of investments	443,300	483,360	1,931,656
Other	1,339	978	(2,532)
Net cash provided by (used for) investing activities	(47,262)	(639,657)	781,165
Net cash flows from financing activities:
Issuance of debt, net of issuance costs	2,095,559	1,020,050	363,595
Other changes in short-term borrowings, net	23,324	204,882	298,659
Repayment of debt	(1,401,104)	(962,515)	(1,316,494)
Net change in other secured financings	1,248	116,702	205,231
Net change in bank overdrafts	(5,650)	(46,536)	0
Issuance of common shares	1,501	1,062	1,223
Net contributions from (distributions to) redeemable noncontrolling interests	(90,233)	(52,889)	5,165
Distributions to noncontrolling interests	(12,031)	(18,544)	(7,277)
Contributions from noncontrolling interests	40,072	154,522	15,469
Purchase of common shares for treasury	(100,477)	(95,020)	(125,754)
Dividends paid	(117,407)	(91,296)	(92,550)
Other	(1)	488	750
Net cash provided by (used for) financing activities	434,801	230,906	(651,983)
Effect of foreign exchange rate changes on cash	10,687	(25,980)	(5,554)
Change in cash classified as assets held for sale	(3,136)	(5,206)	0
Net increase (decrease) in cash and cash equivalents	1,467,922	168,910	(638,127)
Cash and cash equivalents at January 1,	3,807,558	3,638,648	4,276,775
Cash and cash equivalents at December 31,	$ 5,275,480	$ 3,807,558	$ 3,638,648