LPL Financial (LPLA) 10-K 21 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 14, 2018	Jun. 30, 2017
Entity Information [Line Items]
Entity Registrant Name	LPL Financial Holdings Inc.
Entity Central Index Key	1,397,911
Current Fiscal Year End Date	--12-31
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Amendment Flag	false
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 3,796,785,811
Entity Common Stock, Shares Outstanding		90,041,309

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUES:
Commission	$ 1,670,824	$ 1,737,435	$ 1,976,845
Advisory	1,409,247	1,289,681	1,352,454
Asset-based	708,333	556,475	493,687
Transaction and fee	424,667	415,715	401,948
Interest income, net of interest expense	24,473	21,282	19,192
Other	43,937	28,795	30,928
Total net revenues	4,281,481	4,049,383	4,275,054
EXPENSES:
Commission and advisory	2,669,599	2,600,624	2,864,813
Compensation and benefits	456,918	436,557	440,049
Promotional	171,661	148,612	139,198
Depreciation and amortization	84,071	75,928	73,383
Amortization of Intangible Assets	38,293	38,035	38,239
Professional services	71,407	67,128	64,522
Occupancy and equipment	97,332	92,956	84,112
Brokerage, clearing, and exchange	57,047	54,509	52,516
Communications and data processing	44,941	44,453	46,871
Restructuring charges	0	0	11,967
Other	96,210	96,587	117,693
Total operating expenses	3,787,479	3,655,389	3,933,363
Non-operating interest expense	107,025	96,478	59,136
Loss on extinguishment of debt	(22,407)	0	0
INCOME BEFORE PROVISION FOR INCOME TAXES	364,570	297,516	282,555
PROVISION FOR INCOME TAXES	125,707	105,585	113,771
NET INCOME	$ 238,863	$ 191,931	$ 168,784
EARNINGS PER SHARE (Note 15)
Earnings per share, basic	$ 2.65	$ 2.15	$ 1.77
Earnings per share, diluted	$ 2.59	$ 2.13	$ 1.74
Weighted-average shares outstanding, basic	90,002	89,072	95,273
Weighted-average shares outstanding, diluted	92,115	90,013	96,786

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	$ 187	$ 95	$ 132
Net income	238,863	191,931	168,784
Other comprehensive income, net of tax:
Unrealized gain on cash flow hedges, net of tax expense of $187, $95, and $132 for the years ended December 31, 2017, 2016, and 2015, respectively	293	150	179
Reclassification adjustment for realized gain on cash flow hedges included in professional services in the consolidated statements of income, net of tax expense of $406, $252, and $353 for the years ended December 31, 2017, 2016, and 2015, respectively	(608)	(388)	(563)
Total other comprehensive income, net of tax	(315)	(238)	(384)
Total comprehensive income	$ 238,548	$ 191,693	$ 168,400

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	$ 187	$ 95	$ 132
Tax expense (benefit) on adjustment for items reclassified to earnings	$ (406)	$ (252)	$ (353)

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 811,136	$ 747,709
Cash and securities segregated under federal and other regulations	763,831	768,219
Restricted Cash	50,688	42,680
Receivables from:
Clients, net	344,230	341,199
Product sponsors, broker-dealers and clearing organizations	196,207	175,122
Advisor loans, net	219,157	194,526
Others, net	228,986	189,632
Securities owned:
Trading — at fair value	17,879	11,404
Held-to-maturity	11,833	8,862
Securities borrowed	12,489	5,559
Fixed assets, net	412,684	387,368
Goodwill	1,427,769	1,365,838
Intangible assets, net	414,093	353,996
National Planning Holdings acquisition	162,500	0
Other assets	285,269	242,812
Total assets	5,358,751	4,834,926
LIABILITIES:
Drafts payable	185,929	198,839
Payables to clients	962,891	863,765
Payables to broker-dealers and clearing organizations	54,262	63,032
Accrued commission and advisory expenses payable	147,095	128,476
Accounts payable and accrued liabilities	461,149	385,545
Income taxes payable	469	4,607
Unearned revenue	72,222	62,785
Securities sold, but not yet purchased — at fair value	1,182	183
Long-term borrowings, net	2,385,022	2,175,436
Leasehold financing and capital lease obligations	107,518	105,649
Deferred income taxes, net	16,004	25,614
Total liabilities	4,393,743	4,013,931
STOCKHOLDERS' EQUITY:
Common stock, $0.001 par value; 600,000,000 shares authorized; 123,030,383 shares and 119,917,854 shares issued at December 31, 2017 and 2016, respectively	123	120
Additional paid-in capital	1,556,117	1,445,256
Treasury stock, at cost — 33,262,115 shares and 30,621,270 shares at December 31, 2017 and 2016, respectively	(1,309,568)	(1,194,645)
Accumulated other comprehensive income	0	315
Retained earnings	718,336	569,949
Total stockholders' equity	965,008	820,995
Total liabilities and stockholders' equity	$ 5,358,751	$ 4,834,926

Consolidated Statements of Fin6

Consolidated Statements of Financial Condition (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	123,030,383	119,917,854
Treasury stock, shares	33,262,115	30,621,270
Receivables from clients [Member]
Allowance for Doubtful Accounts Receivable	$ 466	$ 1,580
Advisor Loans [Member]
Allowance for Doubtful Accounts Receivable	$ 3,264	$ 1,852

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
BEGINNING BALANCE at Dec. 31, 2014	$ 971,600	$ 118	$ 1,355,085	$ (780,661)	$ 937	$ 396,121
BEGINNING BALANCE, shares at Dec. 31, 2014		118,235		21,090
Net income and other comprehensive income, net of tax expense	168,400				(384)	168,784
Issuance of common stock to settle restricted stock units	(3,018)	$ 1		$ (3,019)
Issuance of common stock to settle restricted stock units, shares		184		68
Treasury stock purchases	(390,835)			$ (390,835)
Treasury stock purchases, shares				8,947
Cash dividends on common stock	(95,814)					(95,814)
Stock options exercises and other	33,030		30,966	$ 2,025		39
Stock options exercises and other, shares		1,153		(57)
Excess tax benefits from share-based compensation	3,034		3,034
Share-based compensation	29,213		29,213
Share-based compensation, shares
ENDING BALANCE at Dec. 31, 2015	715,610	$ 119	1,418,298	$ (1,172,490)	553	469,130
ENDING BALANCE, shares at Dec. 31, 2015		119,572		30,048
Net income and other comprehensive income, net of tax expense	191,693				(238)	191,931
Issuance of common stock to settle restricted stock units	(1,241)	$ 1		$ (1,242)
Issuance of common stock to settle restricted stock units, shares		154		53
Treasury stock purchases	(25,013)			$ (25,013)
Treasury stock purchases, shares				635
Cash dividends on common stock	(89,081)					(89,081)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		192		(115)
Stock options exercises and other	6,865		4,796	$ 4,100		(2,031)
Excess tax benefits from share-based compensation	(2,734)		(2,734)
Share-based compensation	24,896		24,896
ENDING BALANCE at Dec. 31, 2016	820,995	$ 120	1,445,256	$ (1,194,645)	315	569,949
ENDING BALANCE, shares at Dec. 31, 2016		119,918		30,621
Net income and other comprehensive income, net of tax expense	238,548				(315)	238,863
Issuance of common stock to settle restricted stock units	(3,461)			$ (3,461)
Issuance of common stock to settle restricted stock units, shares		366		84
Treasury stock purchases	$ (113,728)			$ (113,728)
Treasury stock purchases, shares	2,619,532			2,620
Cash dividends on common stock	$ (90,273)					(90,273)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	2,727,774	2,746		(63)
Stock options exercises and other	$ 84,405	$ 3	82,339	$ 2,266		(203)
Share-based compensation	28,522		28,522
ENDING BALANCE at Dec. 31, 2017	$ 965,008	$ 123	$ 1,556,117	$ (1,309,568)	$ 0	$ 718,336
ENDING BALANCE, shares at Dec. 31, 2017		123,030		33,262

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 238,863	$ 191,931	$ 168,784
Noncash items:
Depreciation and amortization	84,071	75,928	73,383
Amortization of Intangible Assets	38,293	38,035	38,239
Amortization of debt issuance costs	4,304	5,752	3,405
Share-based compensation	28,522	24,896	29,213
Excess tax benefits related to share-based compensation	0	(65)	(3,810)
Provision for bad debts, net of recoveries	2,789	4,057	2,542
Deferred income taxes	(9,391)	(11,550)	(30,153)
Gain (Loss) on Extinguishment of Debt	22,407	0	0
Loan forgiveness	53,660	45,163	37,658
Other	(14,206)	(3,805)	1,304
Changes in operating assets and liabilities:
Cash and securities segregated under federal and other regulations	4,388	(96,880)	(102,409)
Increase (Decrease) in Restricted Cash for Operating Activities	(20,696)	(20,628)	(32,139)
Decrease in Restricted Cash Operating Activities	12,692	4,407	6,550
Receivables from clients	(1,916)	(2,226)	26,081
Receivables from product sponsors, broker-dealers and clearing organizations	(21,085)	(13,899)	16,247
Advisor Loans	(79,703)	(91,866)	(66,312)
Receivables from others	(32,618)	(12,466)	(10,514)
Securities owned	(5,276)	835	144
Securities borrowed	(6,930)	442	(966)
Other assets	(23,156)	(30,013)	(30,714)
Drafts payable	(12,910)	9,757	8,984
Payables to clients	99,126	116,344	94,707
Payables to broker-dealers and clearing organizations	(8,770)	15,000	2,605
Accrued commissions and advisory expenses payable	18,619	(1,036)	(16,992)
Accounts payable and accrued liabilities	66,404	33,512	50,077
Income taxes receivable/payable	(4,138)	(4,008)	12,574
Unearned revenue	9,437	(2,695)	998
Securities sold, but not yet purchased	999	(85)	(35)
Net cash provided by operating activities	443,779	274,837	279,451
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(111,910)	(127,646)	(72,565)
Purchase of goodwill and other intangible assets	(160,321)	0	0
Proceeds from disposal of fixed assets	12	0	10
Purchase of securities classified as held-to-maturity	(5,969)	(4,020)	(4,602)
Proceeds from maturity of securities classified as held-to-maturity	3,000	5,000	3,350
National Planning Holdings acquisition	(162,500)	0	0
Deposits of restricted cash	(4)	(65)	(1,750)
Release of restricted cash	0	1,445	609
Net cash used in investing activities	(437,692)	(125,286)	(74,948)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit facility	0	0	456,000
Repayments of revolving credit facility	0	0	(566,000)
Repayment of senior secured term loans	(2,405,360)	(17,677)	(9,221)
Proceeds from senior secured term loans	2,611,593	0	693,000
Payment of debt issuance costs	(23,798)	0	(13,258)
Tax payments related to settlement of restricted stock units	(3,461)	(1,241)	(3,018)
Repurchase of common stock	(113,728)	(25,013)	(390,835)
Dividends on common stock	(90,273)	(89,081)	(95,814)
Excess tax benefits related to share-based compensation	0	65	3,810
Proceeds from stock option exercises and other	84,405	6,865	33,030
Payment of Leasehold Financing Obligation	(2,038)	(289)	0
Net cash provided by (used in) financing activities	57,340	(126,371)	107,694
NET INCREASE IN CASH AND CASH EQUIVALENTS	63,427	23,180	312,197
CASH AND CASH EQUIVALENTS - Beginning of year	747,709	724,529	412,332
CASH AND CASH EQUIVALENTS - End of year	811,136	747,709	724,529
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest paid	92,650	92,344	51,114
Income taxes paid	139,200	122,909	131,833
NONCASH DISCLOSURES:
Capital expenditures included in accounts payable and accrued liabilities	16,096	24,339	11,462
Finance and capital lease obligations	3,906	45,998	59,940
Discount on proceeds from senior secured credit facilities recorded as debt issuance costs	$ 5,040	$ 0	$ 7,000

Organization and Description of

Organization and Description of the Company	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of the Company	Organization and Description of the Company LPL Financial Holdings Inc. ( “ LPLFH ” ), a Delaware holding corporation, together with its consolidated subsidiaries (collectively, the “ Company ” ) provides an integrated platform of brokerage and investment advisory services to independent financial advisors and financial advisors at financial institutions (collectively “ advisors ” ) in the United States. Through its custody and clearing platform, using both proprietary and third-party technology, the Company provides access to diversified financial products and services, enabling its advisors to offer independent financial advice and brokerage services to retail investors (their “ clients ” ). Description of Subsidiaries LPL Holdings, Inc. ( “ LPLH ” ), a Massachusetts holding corporation, owns 100% of the issued and outstanding common stock or other ownership interest in each of LPL Financial LLC ("LPL Financial"), Fortigent Holdings Company, Inc., and LPL Insurance Associates, Inc. ( “ LPLIA ” ). LPLH is also the majority stockholder in PTC Holdings, Inc. ( “ PTCH ” ), and owns 100% of the issued and outstanding voting common stock. Each member of PTCH's board of directors meets the direct equity ownership interest requirements that are required by the Office of the Comptroller of the Currency. The Company has established a wholly-owned series captive insurance entity that underwrites insurance for various legal and regulatory risks. LPL Financial, with primary offices in San Diego, California; Fort Mill, South Carolina; and Boston, Massachusetts, is a clearing broker-dealer and an investment adviser that principally transacts business as an agent for its advisors and financial institutions on behalf of their clients in a broad array of financial products and services. LPL Financial is licensed to operate in all 50 states, Washington D.C., Puerto Rico, and the U.S. Virgin Islands. Fortigent Holdings Company, Inc. and its subsidiaries ( “ Fortigent ” ) provides solutions and consulting services to registered investment advisors, banks, and trust companies serving high-net-worth clients. PTCH is a holding company for The Private Trust Company, N.A. ( “ PTC ” ). PTC is chartered as a non-depository limited purpose national bank, providing a wide range of trust, investment management oversight, and custodial services for estates and families. PTC also provides Individual Retirement Account custodial services for LPL Financial.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation These consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States ( “ GAAP ” ), which require the Company to make estimates and assumptions regarding the valuation of certain financial instruments, intangible assets, allowance for doubtful accounts, share-based compensation, accruals for liabilities, income taxes, revenue and expense accruals, and other matters that affect the consolidated financial statements and related disclosures. Actual results could differ from those estimates under different assumptions or conditions and the differences may be material to the consolidated financial statements. Consolidation These consolidated financial statements include the accounts of LPLFH and its subsidiaries. Intercompany transactions and balances have been eliminated. Equity investments over which the Company exercises significant influence, but does not exercise control and is not the primary beneficiary, are accounted for using the equity method. Reportable Segment Management has determined that the Company operates in one segment, given the similarities in economic characteristics between its operations and the common nature of its products and services, production and distribution process, and regulatory environment. Revenue Recognition Substantially all of the Company's revenues are based on contractual arrangements. In determining the appropriate recognition of commissions, the Company reviews the terms and conditions of the brokerage account agreements between the Company and its advisors' clients, representative agreements with its advisors, which include payout rates and terms, and selling agreements with product sponsors for packaged investment products such as mutual funds, annuities, insurance, and alternative investments. In determining the appropriate recognition of advisory revenues, the Company reviews the terms and conditions of the advisory agreements between the advisors' clients and the applicable registered investment advisor ( “ RIA ” ), representative agreements with its advisors, and agreements with third parties who provide specific investment management or investment strategies. Revenues are recognized in the periods in which the related services are performed provided that persuasive evidence of an arrangement exists, the fee is fixed or determinable, and collectability is reasonably assured. Payments received by the Company in advance of the performance of service are deferred and recognized as revenue when earned. Management considers the nature of the Company's contractual arrangements in determining whether to recognize certain types of revenue on the basis of the gross amount billed or net amount retained after payments are made to providers of certain services related to the product or service offering. The main factors the Company uses to determine whether to record revenue on a gross or net basis are whether: • the Company is primarily responsible for the service to the advisor and their client; • the Company has discretion in establishing fees paid by the client and fees due to the third-party service provider; and • the Company is involved in the determination of product or service specifications. When client fees include a portion of charges that are paid to another party and the Company is primarily responsible for providing the service to the client, revenue is recognized on a gross basis in an amount equal to the fee paid by the client. The cost of revenues recognized is the amount due to the other party and is recorded as commission and advisory expense in the consolidated statements of income. In instances in which another party is primarily responsible for providing the service to the client, revenue is recognized in the net amount retained by the Company. The portion of the fees that are collected from the client by the Company and remitted to the other party are considered pass-through amounts and accordingly are not a component of revenues or cost of revenues. Commission Revenues Commission revenues represent commissions generated by the Company's advisors for their clients' purchases and sales of securities on exchanges and over-the-counter, as well as purchases of various investment products such as mutual funds, variable and fixed annuities, alternative investments including non-traded real estate investment trusts and business development companies, fixed income, insurance, group annuities, and option and commodity transactions. The Company generates two types of commission revenues: transaction-based sales commissions that occur at the point of sale, as well as trailing commissions for which the Company provides ongoing support, awareness, and education to clients of its advisors. Transaction-based sales commissions are recognized as revenue on a trade-date basis, which is when the Company's performance obligations in generating the commissions have been substantially completed. The Company settles a significant volume of transactions that are initiated directly between its advisors and product sponsors, particularly with regard to mutual fund, 529 education savings plan, fixed and variable annuity, and insurance products. As a result, management must estimate a portion of its commission revenues earned from clients for purchases and sales of these products for each accounting period for which the proceeds have not yet been received. These estimates are based on the amount of commissions earned from transactions in these products in prior periods. Trailing commission revenues include mutual fund, 529 education savings plan, and fixed and variable product trailing fees that are recurring in nature. These trailing fees are earned by the Company based on a percentage of the current market value of clients' investment holdings in trail-eligible assets, and recognized over the period during which services are performed. Because trailing commission revenues are generally paid in arrears, management estimates the majority of trailing commission revenues earned during each period. These estimates are based on a number of factors, including market levels and the amount of trailing commission revenues received in prior periods. Commission revenue accruals are classified within receivables from product sponsors, broker-dealers, and clearing organizations in the consolidated statements of financial condition. A substantial portion of the commission revenue is ultimately paid to the advisors. The Company records an estimate for commissions payable based upon average payout ratios for each product for which the Company has accrued commission revenue. Such amounts are classified as accrued commission and advisory expenses payable in the consolidated statements of financial condition and commission and advisory expense in the consolidated statements of income. Advisory Revenues The Company records fees charged to clients as advisory revenues in advisory accounts where LPL Financial is the RIA firm. A substantial portion of these advisory fees are paid to the related advisor and these payments are classified as commission and advisory expense in the consolidated statements of income. Certain advisors conduct their advisory business through separate entities by establishing their own RIA firm pursuant to the Advisers Act or through their respective states' investment advisory licensing rules, rather than using the Company's corporate RIA platform. These independent entities, or Hybrid RIAs, engage the Company for clearing, regulatory, and custody services, including oversight of assets held at third-party custodians, as well as access to the Company's investment advisory platforms. The advisory revenue generated by these Hybrid RIAs is earned by the advisors, and accordingly not included in the Company's advisory revenues. The Company charges separate fees to Hybrid RIAs for technology, custody, administrative, and clearing services, primarily based on the value of assets within these advisory accounts, which are classified as advisory revenues in the consolidated statements of income. Asset-Based Revenues Asset-based revenues are comprised of fees from cash sweep programs, financial product manufacturer sponsorship programs, and omnibus processing and networking services and are recognized ratably over the period in which services are provided. Transaction and Fee Revenues The Company charges fees for executing certain transactions in client accounts. Transaction related charges are recognized on a trade-date basis. Other fees relate to services provided and other account charges generally outlined in agreements with clients, advisors, and financial institutions. Such fees are recognized as services are performed or as earned, as applicable. In addition, the Company offers various services for which fees are charged on a subscription basis and recognized over the subscription period. Interest Income, Net of Interest Expense The Company earns interest income from its cash equivalents and client margin balances, less interest expense on related transactions. Because interest expense incurred in connection with cash equivalents and client margin balances is completely offset by revenue on related transactions, the Company considers such interest to be an operating expense. Interest expense from operations for the years ended December 31, 2017 , 2016 , and 2015 did not exceed $1.0 million . Compensation and Benefits The Company records compensation and benefits expense for all cash and deferred compensation, benefits, and related taxes as earned by its employees. Compensation and benefits expense also includes fees earned by temporary employees and contractors who perform similar services to those performed by the Company’s employees, primarily software development and project management activities. Share-Based Compensation Certain employees, officers, directors, advisors, and financial institutions of the Company participate in various long-term incentive plans that provide for granting stock options, warrants, restricted stock awards, restricted stock units, deferred stock units and performance stock units. Stock options, warrants and restricted stock units generally vest in equal increments over a three year period and expire on the tenth anniversary following the date of grant. Restricted stock awards and deferred stock units generally vest over a one year period, and performance stock units generally vest in full at the end of a three-year performance period. The Company recognizes share-based compensation for equity awards granted to employees, officers, and directors as compensation and benefits expense on the consolidated statements of income. The fair value of stock options is estimated using a Black-Scholes valuation model on the date of grant. The fair value of restricted stock awards, restricted stock units, and deferred stock units is equal to the closing price of the Company’s stock on the date of grant. The fair value of performance stock units is estimated using a Monte-Carlo simulation model on the date of grant. Share-based compensation is recognized over the requisite service period of the individual awards, which generally equals the vesting period. The Company recognizes share-based compensation for equity awards granted to advisors and financial institutions as commissions and advisory expense on the consolidated statements of income. The fair value of stock options and warrants is estimated using a Black-Scholes valuation model on the date of grant and is revalued at each reporting period. The fair value of restricted stock units is equal to the closing price of the Company’s stock on the date of grant and on the last day of each reporting period. Share-based compensation is recognized over the requisite service period of the individual awards, which generally equals the vesting period. The Company also makes assumptions regarding the number of stock options, warrants, restricted stock awards, restricted stock units, deferred stock units and performance stock units that will be forfeited. The forfeiture assumption is ultimately adjusted to the actual forfeiture rate. Therefore, changes in the forfeiture assumptions do not impact the total amount of expense ultimately recognized over the vesting period. Rather, different forfeiture assumptions would only impact the timing of expense recognition over the vesting period. See Note 14 . Share-Based Compensation , for additional information regarding share-based compensation for equity awards granted. Earnings Per Share Basic earnings per share is computed by dividing net income available to common shareholders by the basic weighted-average number of shares of common stock outstanding during the period. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased to include the number of additional shares of common stock that would have been outstanding if dilutive potential shares of common stock had been issued. Income Taxes In preparing the consolidated financial statements, the Company estimates income tax expense based on various jurisdictions where it conducts business. The Company then must assess the likelihood that the deferred tax assets will be realized. A valuation allowance is established to the extent that it is more-likely-than-not that such deferred tax assets will not be realized. When the Company establishes a valuation allowance or modifies the existing allowance in a certain reporting period, it generally records a corresponding increase or decrease to tax expense in the consolidated statements of income. Management makes significant judgments in determining the provision for income taxes, the deferred tax assets and liabilities, and any valuation allowances recorded against the deferred tax asset. Changes in the estimate of these taxes occur periodically due to changes in the tax rates, changes in the business operations, implementation of tax planning strategies, resolution with taxing authorities of issues where the Company had previously taken certain tax positions, and newly enacted statutory, judicial, and regulatory guidance. These changes could have a material effect on the Company’s consolidated statements of income, financial condition, or cash flows in the period or periods in which they occur. Income tax credits are accounted for using the flow-through method as a reduction of income tax in the years utilized. The Company recognizes the tax effects of a position in the consolidated financial statements only if it is more-likely-than-not to be sustained based solely on its technical merits; otherwise no benefits of the position are to be recognized. The more-likely-than-not threshold must continue to be met in each reporting period to support continued recognition of a benefit. Moreover, each tax position meeting the recognition threshold is required to be measured as the largest amount that is greater than 50 percent likely to be realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. Cash and Cash Equivalents Cash equivalents are highly liquid investments with an original maturity of 90 days or less that are not required to be segregated under federal or other regulations. The Company's cash and cash equivalents are composed of interest and noninterest-bearing deposits, money market funds, and United States government obligations. Cash and Securities Segregated Under Federal and Other Regulations The Company's subsidiary, LPL Financial, is subject to requirements related to maintaining cash or qualified securities in a segregated reserve account for the exclusive benefit of its customers in accordance with Rule 15c3-3 of the Security Exchange Act of 1934, as amended, and other regulations. Held within this account is approximately $100,000 for the proprietary accounts of introducing brokers. Restricted Cash Restricted cash primarily represents cash held by and for use by the Company’s captive insurance subsidiary. Receivables From and Payables to Clients Receivables from clients include amounts due on cash and margin transactions. The Company extends credit to clients of its advisors to finance their purchases of securities on margin and receives income from interest charged on such extensions of credit. Payables to clients represent credit balances in client accounts arising from deposits of funds, proceeds from sales of securities, and dividend and interest payments received on securities held in client accounts at LPL Financial. At December 31, 2017 and 2016 , $920.1 million and $836.6 million , respectively, of the balance represent free credit balances that are held pending re-investment by the clients. The Company pays interest on certain client payable balances. To the extent that margin loans and other receivables from clients are not fully collateralized by client securities, management establishes an allowance that it believes is sufficient to cover any probable losses. When establishing this allowance, management considers a number of factors, including its ability to collect from the client or the client’s advisor and the Company’s historical experience in collecting on such transactions. The following schedule reflects the Company’s activity in providing for an allowance for uncollectible amounts due from clients (in thousands): December 31, 2017 2016 Beginning balance — January 1 $ 1,580 $ 1,464 Provision for bad debts, net of recoveries (15 ) 116 Charge-offs (1,099 ) — Ending balance — December 31 $ 466 $ 1,580 Advisor Loans The Company periodically extends credit to its advisors in the form of recruiting loans, commission advances, and other loans. The decisions to extend credit to advisors are generally based on the advisors’ credit history and their ability to generate future commissions. Certain loans made in connection with recruiting are forgivable over terms ranging from three to eight years provided that the advisor remains licensed through LPL Financial. At December 31, 2017 , $159.9 million of the advisor loan balance was forgivable. If an advisor terminates their arrangement with the Company prior to the forgivable loan term date or repayment of another loan, an allowance for uncollectible amounts is recorded using an analysis that takes into account the advisors’ registration status and the specific type of receivable. The aging thresholds and specific percentages used represent management’s best estimates of probable losses. Management monitors the adequacy of these estimates through periodic evaluations against actual trends experienced. The following schedule reflects the Company’s activity in providing for an allowance for uncollectible amounts for advisor loans (in thousands): December 31, 2017 2016 Beginning balance — January 1 $ 1,852 $ 697 Provision for bad debts, net of recoveries 951 1,155 Charge-offs (2,914 ) — Reclassification from receivables from others 3,375 — Ending balance — December 31 $ 3,264 $ 1,852 The Company reclassified the provision for bad debt for advisor loans out of the provision for bad debt for receivables from others. Receivables From Others Receivables from others primarily consist of accrued fees from product sponsors and amounts due from advisors. Management maintains an allowance for uncollectible amounts using an aging analysis that takes into account the specific type of receivable. The aging thresholds and specific percentages used represent management’s best estimates of probable losses. Management monitors the adequacy of these estimates through periodic evaluations against actual trends experienced. The following schedule reflects the Company’s activity in providing for an allowance for uncollectible amounts due from others (in thousands): December 31, 2017 2016 Beginning balance — January 1 $ 12,851 $ 9,856 Provision for bad debts, net of recoveries 1,853 2,786 Charge-offs (5,214 ) 209 Reclassification to advisor loans (3,375 ) — Ending balance — December 31 $ 6,115 $ 12,851 Securities Owned and Securities Sold, But Not Yet Purchased Securities owned and securities sold, but not yet purchased include trading and held-to-maturity securities. The Company generally classifies its investments in debt and equity instruments (including mutual funds, annuities, corporate bonds, government bonds, and municipal bonds) as trading securities, except for United States government notes held by PTC, which are classified as held-to-maturity securities. The Company has not classified any investments as available-for-sale. Investment classifications are subject to ongoing review and can change. Securities classified as trading are carried at fair value, while securities classified as held-to-maturity are carried at amortized cost. The Company uses prices obtained from independent third-party pricing services to measure the fair value of its trading securities. Prices received from the pricing services are validated using various methods including comparison to prices received from additional pricing services, comparison to available quoted market prices, and review of other relevant market data including implied yields of major categories of securities. In general, these quoted prices are derived from active markets for identical assets or liabilities. When quoted prices in active markets for identical assets and liabilities are not available, the quoted prices are based on similar assets and liabilities or inputs other than the quoted prices that are observable, either directly or indirectly. For certificates of deposit and treasury securities, the Company utilizes market-based inputs, including observable market interest rates that correspond to the remaining maturities or the next interest reset dates. At December 31, 2017 , the Company did not adjust prices received from the independent third-party pricing services. Interest income is accrued as earned. Premiums and discounts are amortized using a method that approximates the effective yield method over the term of the security and are recorded as an adjustment to the investment yield. The Company makes estimates about the fair value of investments and the timing for recognizing losses based on market conditions and other factors. If these estimates change, the Company may recognize additional losses. Both unrealized and realized gains and losses on trading securities are recognized in other revenue on a net basis in the consolidated statements of income. Securities Borrowed The Company borrows securities from other broker-dealers to make deliveries or to facilitate customer short sales. Securities borrowed are accounted for as collateralized financings and are recorded at contract value, representing the amount of cash provided for securities borrowed transactions (generally in excess of market values). The adequacy of the collateral deposited, which is determined by comparing the market value of the securities borrowed to the cash loaned , is continuously monitored and is adjusted when considered necessary to minimize the risk associated with this activity. As of December 31, 2017 , the contract and collateral market values of borrowed securities were $12.5 million and $12.1 million , respectively. As of December 31, 2016 , the contract and collateral market values of borrowed securities were $5.6 million and $5.4 million , respectively. Fixed Assets Internally developed software, leasehold improvements, computers and software, and furniture and equipment are recorded at historical cost, net of accumulated depreciation and amortization. Depreciation is recognized using the straight-line method over the estimated useful lives of the assets. The Company charges software development costs to operations as incurred during the preliminary project stage, while capitalizing costs at the point at which the conceptual formulation, design, and testing of possible software project alternatives are complete and management authorizes and commits to funding the project. The costs of internally developed software that qualify for capitalization are capitalized as fixed assets and subsequently amortized over the estimated useful life of the software, which is generally three years. The Company does not capitalize pilot projects and projects for which it believes that the future economic benefits are less than probable. Leasehold improvements are amortized over the lesser of their useful lives or the terms of the underlying leases. Computers and software, as well as furniture and equipment, are depreciated over a period of three to seven years. Land is not depreciated. Management reviews fixed assets for impairment whenever events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. No material impairment occurred for the years ended December 31, 2017 , 2016 , and 2015 . Acquisitions When acquiring companies, the Company recognizes separately from goodwill the assets acquired and the liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred and the net of the acquisition date fair values of the assets acquired and the liabilities assumed. While the Company uses its best estimates and assumptions as a part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the consolidated statements of income. Accounting for business combinations requires the Company's management to make significant estimates and assumptions, especially at the acquisition date with respect to intangible assets, support liabilities assumed, and pre-acquisition contingencies. These assumptions are based in part on historical experience, market data, and information obtained from the management of the acquired companies and are inherently uncertain. Examples of critical estimates in valuing certain of the intangible assets the Company has acquired include, but are not limited to: (i) future expected cash flows from assets and advisor relationships; and (ii) discount rates. Goodwill and Other Intangible Assets Goodwill and other indefinite-lived assets are not amortized; however, intangible assets that are deemed to have definite lives are amortized over their useful lives, generally ranging from 5 - 20 years. See Note 8 . Goodwill and Other Intangible Assets , for additional information regarding the Company's goodwill and other intangible assets. Goodwill and other indefinite-lived intangible assets are tested annually for impairment in the fourth fiscal quarter and between annual tests if certain events occur indicating that the carrying amounts may be impaired. If a qualitative assessment is used and the Company determines that the fair value of a reporting unit or indefinite-lived intangible asset is more likely than not (i.e., a likelihood of more than 50%) less than its carrying amount, a quantitative impairment test will be performed. If goodwill or other indefinite-lived intangible assets are quantitatively assessed for impairment, a two-step approach is applied. For goodwill, the Company first compares the estimated fair value of the reporting unit in which the asset resides to its carrying value. For indefinite-lived intangible assets, the Company first compares the estimated fair value of the indefinite-lived intangible asset to its carrying value. The second step, if necessary, measures the amount of such impairment by comparing the implied fair value of the asset to its carrying value. No impairment of goodwill or other indefinite-lived intangible assets was recognized during the years ended December 31, 2017 , 2016 , or 2015 . Long-lived assets, such as intangible assets subject to amortization, are reviewed for impairment when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of an asset or asset group to estimated undiscounted future cash flows expected to be generated by the asset or asset group. If the carrying amount of an asset or asset group exceeds its estimated future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset or asset group exceeds the estimated fair value of the asset or asset group. Long-lived assets to be disposed of by sale are reported at the lower of their carrying amounts or their estimated fair values less costs to sell and are not depreciated. There was no material impairment of definite-lived intangible assets recognized during the years ended December 31, 2017 , 2016 , and 2015 , respectively. Debt Issuance Costs Debt issuance and amendment costs have been capitalized and are being amortized as additional interest expense over the expected terms of the related debt agreements. Debt issuance costs are presented as a direct deduction from the carrying amount of the related debt liability. Costs incurred while obtaining the revolving credit facility are included in other assets and subsequently amortized ratably over the term of the revolving credit facility, regardless of whether there are any outstanding borrowings on the revolving credit facility. Fair Value of Financial Instruments The Company’s financial assets and liabilities are carried at fair value or at amounts that, because of their short-term nature, approximate current fair value, with the exception of its held-to-maturity securities and indebtedness, which are carried at amortized cost. The Company measures the implied fair value of its debt instruments using trading levels obtained from a third-party service provider. Accordingly, the debt instruments qualify as Level 2 fair value measurements. See Note 4 . Fair Value Measurements , for additional information regarding the Company's fair value measurements. As of December 31, 2017 , the carrying amount and fair value of the Company’s indebtedness was approximately $2,396.3 million and $2,422.0 million , respectively. As of December 31, 2016 , the carrying amount and fair value was approximately $2,197.4 million and $2,218.9 million , respectively. Commitments and Contingencies The Company recognizes a liability with regard to loss contingencies when it believes it is probable a liability has occurred and the amount can be reasonably estimated. If some amount within a range of loss appears at the time to be a better estimate than any other amount within the range, the Company accrues that amount. When no amount within the range is a better estimate than any other amount, however, the Company accrues the minimum amount in the range. The Company has established an accrual for those legal proceedings and regulatory matters for which a loss is both probable and the amount can be reasonably estimated, except as otherwise covered by third-party insurance or self-insurance through the Company's captive insurance subsidiary. Assessing the probability of a loss occurring and the timing and amount of any loss related to a legal proceeding or regulatory matter is inherently difficult and requires management to make significant judgments. For additional information, see Note 12, Commitments and Contingencies - Legal & Regulatory Matters. Leasehold Financing Obligation The Company was involved in a build-to-suit lease arrangement in Fort Mill, South Carolina, under which it served as the construction agent on behalf of the landlord and bore substantially all of the risks and rewards of ownership as measured under GAAP. The Company was therefore required to report the landlord's costs of construction as a fixed asset during the construction period as if the Company owned such asset and an equal and off-setting leasehold financing obligation on our consolidated statements of financial condition. The construction was completed in October 2016 and it was determined that the asset did not qualify for sale-leaseback accounting treatment.

Acquisitions (Notes)

Acquisitions (Notes)	12 Months Ended
	Dec. 31, 2017
Acquisitions [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions On August 15, 2017, the Company entered into an asset purchase agreement ("Asset Purchase Agreement") with National Planning Holdings, Inc. (“NPH”), and its four broker-dealer subsidiaries (collectively with NPH, “NPH Sellers”) to acquire certain assets and rights of the NPH Sellers, including business relationships with financial advisors who become affiliated with the Company. In accordance with ASC 805, Business Combinations, control will transfer when the Company begins to onboard NPH advisors and client assets onto its platform, which will occur in two waves. The first wave was completed in the fourth quarter of 2017 and the Company anticipates completing the conversion by the end of the first quarter of 2018 (the "Conversion Period"). The Company paid $325 million to the NPH Sellers at closing, which occurred on August 15, 2017 and is included in the National Planning Holdings acquisition line on the consolidated statements of financial condition. Following the completion of the first wave in the fourth quarter of 2017, the Company recorded intangible assets of $98.4 million in advisor relationships and $61.9 million in goodwill acquired in the purchase. The Company has agreed to a potential contingent payment of up to $122.8 million (the “Contingent Payment”), following the conclusion of the Conversion Period, which will be calculated based on the percentage of aggregate trailing twelve-month gross dealer concessions (“GDC”) in respect of NPH Sellers’ client accounts that transfer to the Company, as determined under the Asset Purchase Agreement. The Contingent Payment would be paid on an interpolated basis based on the percentage of transferred GDC between 72% and 93.5% and in the event that the percentage is less than 72%

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Inputs used to measure fair value are prioritized within a three-level fair value hierarchy. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1 — Quoted prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. This includes certain pricing models, discounted cash flow methodologies, and similar techniques that use significant unobservable inputs. There have been no transfers of assets or liabilities between these fair value measurement classifications during the years ended December 31, 2017 and 2016 . The Company’s fair value measurements are evaluated within the fair value hierarchy, based on the nature of inputs used to determine the fair value at the measurement date. At December 31, 2017 and December 31, 2016 , the Company had the following financial assets and liabilities that are measured at fair value on a recurring basis: Cash Equivalents — The Company’s cash equivalents include money market funds, which are short term in nature with readily determinable values derived from active markets. Securities Owned and Securities Sold, But Not Yet Purchased — The Company’s trading securities consist of house account model portfolios established and managed for the purpose of benchmarking the performance of its fee-based advisory platforms and temporary positions resulting from the processing of client transactions. Examples of these securities include money market funds, United States treasury obligations, mutual funds, certificates of deposit, and traded equity and debt securities. The Company uses prices obtained from independent third-party pricing services to measure the fair value of its trading securities. Prices received from the pricing services are validated using various methods including comparison to prices received from additional pricing services, comparison to available quoted market prices, and review of other relevant market data including implied yields of major categories of securities. In general, these quoted prices are derived from active markets for identical assets or liabilities. When quoted prices in active markets for identical assets and liabilities are not available, the quoted prices are based on similar assets and liabilities or inputs other than the quoted prices that are observable, either directly or indirectly. For certificates of deposit and treasury securities, the Company utilizes market-based inputs, including observable market interest rates that correspond to the remaining maturities or the next interest reset dates. At December 31, 2017 and December 31, 2016 , the Company did not adjust prices received from the independent third-party pricing services. Other Assets — The Company’s other assets include: (1) deferred compensation plan assets that are invested in money market and other mutual funds, which are actively traded and valued based on quoted market prices; (2) certain non-traded real estate investment trusts and auction rate notes, which are valued using quoted prices for identical or similar securities and other inputs that are observable or can be corroborated by observable market data; and (3) cash flow hedges, which are measured using quoted prices for similar cash flow hedges, taking into account counterparty credit risk and the Company's own non-performance risk. Accounts Payable and Accrued Liabilities — The Company's accounts payable and accrued liabilities include hedges that are measured using Level 2 inputs and contingent consideration liabilities that are measured using Level 3 inputs. Level 3 Recurring Fair Value Measurements The Company determines the fair value for its contingent consideration obligations using an income approach whereby the Company assesses the expected future performance of the acquired assets. The contingent payment is estimated using a discounted cash flow of the expected payment amount to calculate the fair value as of the valuation date. The Company's management evaluates the underlying projections and other related factors used in determining fair value each period and makes updates when there have been significant changes in management's expectations. The following table summarizes the Company’s financial assets and financial liabilities measured at fair value on a recurring basis at December 31, 2017 (in thousands): Level 1 Level 2 Level 3 Total Assets Cash equivalents $ 147,034 $ — $ — $ 147,034 Securities owned — trading: Money market funds 288 — — 288 Mutual funds 10,850 — — 10,850 Equity securities 201 — — 201 Debt securities — 60 — 60 U.S. treasury obligations 6,480 — — 6,480 Total securities owned — trading 17,819 60 — 17,879 Other assets 180,377 9,282 — 189,659 Total assets at fair value $ 345,230 $ 9,342 $ — $ 354,572 Liabilities Securities sold, but not yet purchased: Mutual funds $ 3 $ — $ — $ 3 Equity securities 67 — — 67 Debt securities — 1,112 — 1,112 Total securities sold, but not yet purchased 70 1,112 — 1,182 Total liabilities at fair value $ 70 $ 1,112 $ — $ 1,182 The following table summarizes the Company’s financial assets and liabilities measured at fair value on a recurring basis at December 31, 2016 (in thousands): Level 1 Level 2 Level 3 Total Assets Cash equivalents $ 168,320 $ — $ — $ 168,320 Securities owned — trading: Money market funds 474 — — 474 Mutual funds 7,585 — — 7,585 Equity securities 35 — — 35 Debt securities — 314 — 314 U.S. treasury obligations 2,996 — — 2,996 Total securities owned — trading 11,090 314 — 11,404 Other assets 134,914 7,105 — 142,019 Total assets at fair value $ 314,324 $ 7,419 $ — $ 321,743 Liabilities Securities sold, but not yet purchased: Equity securities $ 168 $ — $ — $ 168 Debt securities — 15 — 15 Total securities sold, but not yet purchased 168 15 — 183 Accounts payable and accrued liabilities — 86 527 613 Total liabilities at fair value $ 168 $ 101 $ 527 $ 796 Changes in Level 3 Recurring Fair Value Measurements At December 31, 2017

Held-to-Maturity Securities

Held-to-Maturity Securities	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Held-to-Maturity Securities	Held-to-Maturity Securities The Company holds certain investments in securities, primarily United States government notes, which are recorded at amortized cost because the Company has both the intent and the ability to hold these investments to maturity. Interest income is accrued as earned. Premiums and discounts are amortized using a method that approximates the effective yield method over the term of the security and are recorded as an adjustment to the investment yield. The amortized cost, gross unrealized loss, and fair value of securities held-to-maturity were as follows (in thousands): December 31, 2017 2016 Amortized cost $ 11,833 $ 8,862 Gross unrealized loss (86 ) (31 ) Fair value $ 11,747 $ 8,831 At December 31, 2017 , the securities held-to-maturity were scheduled to mature as follows (in thousands): Within one year After one but within five years After five but within ten years Total U.S. government notes — at amortized cost $ 5,006 $ 6,327 $ 500 $ 11,833 U.S. government notes — at fair value $ 4,986 $ 6,266 $ 495 $ 11,747

Receivables from Product Sponso

Receivables from Product Sponsors, Broker-Dealers and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations	12 Months Ended
	Dec. 31, 2017
Due to and from Broker-Dealers and Clearing Organizations [Abstract]
Receivables from Product Sponsors, Broker-Dealers and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations	Receivables from Product Sponsors, Broker-Dealers, and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations Receivables from product sponsors, broker-dealers, and clearing organizations and payables to broker-dealers and clearing organizations were as follows (in thousands): December 31, 2017 2016 Receivables: Commissions receivable from product sponsors and others $ 125,891 $ 116,218 Receivable from clearing organizations 62,561 50,656 Receivable from broker-dealers 1,389 1,309 Securities failed-to-deliver 6,366 6,939 Total receivables $ 196,207 $ 175,122 Payables: Payable to clearing organizations $ 13,316 $ 26,517 Payable to broker-dealers 31,869 32,065 Securities failed-to-receive 9,077 4,450 Total payables $ 54,262 $ 63,032

Fixed Assets

Fixed Assets	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Fixed Assets	Fixed Assets The components of fixed assets were as follows (in thousands): December 31, 2017 2016 Internally developed software $ 346,029 $ 293,997 Leasehold improvements 82,413 86,171 Computers and software 160,400 122,442 Buildings 105,939 105,939 Furniture and equipment 73,767 74,492 Land 4,678 4,678 Construction in progress 66,802 55,568 Total fixed assets 840,028 743,287 Accumulated depreciation and amortization (427,344 ) (355,919 ) Fixed assets, net $ 412,684 $ 387,368 Depreciation and amortization expense was $84.1 million , $75.9 million , and $73.4 million for the years ended December 31, 2017 , 2016 , and 2015

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets A summary of the activity in goodwill is presented below (in thousands): Balance at December 31, 2015 $ 1,365,838 Goodwill acquired — Balance at December 31, 2016 $ 1,365,838 Goodwill acquired 61,931 Balance at December 31, 2017 $ 1,427,769 The components of intangible assets were as follows at December 31, 2017 (dollars in thousands): Weighted-Average Life Remaining (in years) Gross Carrying Value Accumulated Amortization Net Carrying Value Definite-lived intangible assets: Advisor and financial institution relationships 8.0 $ 538,921 $ (269,294 ) $ 269,627 Product sponsor relationships 8.1 234,086 (137,615 ) 96,471 Client relationships 6.8 19,133 (11,477 ) 7,656 Trade names 4.3 1,200 (680 ) 520 Total definite-lived intangible assets $ 793,340 $ (419,066 ) $ 374,274 Indefinite-lived intangible assets: Trademark and trade name 39,819 Total intangible assets $ 414,093 The components of intangible assets were as follows at December 31, 2016 (dollars in thousands): Weighted-Average Life Remaining (in years) Gross Carrying Value Accumulated Amortization Net Carrying Value Definite-lived intangible assets: Advisor and financial institution relationships 9.0 $ 440,533 $ (244,540 ) $ 195,993 Product sponsor relationships 9.1 234,086 (125,620 ) 108,466 Client relationships 7.7 19,133 (10,055 ) 9,078 Trade names 5.3 1,200 (560 ) 640 Total definite-lived intangible assets $ 694,952 $ (380,775 ) $ 314,177 Indefinite-lived intangible assets: Trademark and trade name 39,819 Total intangible assets $ 353,996 Total amortization expense of intangible assets was $38.3 million , $38.0 million , and $38.2 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively. Future amortization expense is estimated as follows (in thousands): 2018 $ 47,678 2019 47,642 2020 47,250 2021 47,093 2022 46,345 Thereafter 138,266 Total $ 374,274

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities Accounts payable and accrued liabilities were as follows (in thousands): December 31, 2017 2016 Advisor deferred compensation plan liability $ 177,652 $ 133,632 Accrued compensation 64,728 63,741 Deferred rent 41,629 43,817 Accounts payable 47,125 23,284 Other accrued liabilities 130,015 121,071 Total accounts payable and accrued liabilities $ 461,149 $ 385,545

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt	Debt On September 21, 2017, LPLFH and LPLH entered into a second amendment (the “Amendment”) to the Company's amended and restated credit agreement, dated March 10, 2017 (as amended by that certain amendment agreement, dated as of June 20, 2017, the Amendment, and as further amended to date, the “Credit Agreement”) and repriced its existing $500.0 million senior secured revolving credit facility and $1,695.8 million senior secured Term Loan B facility ("Term Loan B"). Additionally, LPLH raised $400.0 million in aggregate principal amount of notes (the “Additional Notes”), which were issued above par at 103.0% as an add-on to the Original Notes (as defined below). The Additional Notes issued in the offering are governed by the same indenture, and have the same terms, as the Original Notes. LPLH used $200 million in proceeds from the offering to pay down its Term Loan B to $1,500 million . In connection with the execution of the Amendment, the Company incurred $9.1 million in costs, which are capitalized as debt issuance costs in the consolidated statements of financial condition, and accelerated the recognition of $1.3 million of unamortized debt issuance costs as a loss on extinguishment of debt in the consolidated statements of income. On March 10, 2017, LPLFH and LPLH entered into a fourth amendment agreement, which amended and restated LPLH’s then-existing credit agreement and refinanced LPLH’s then-outstanding senior secured credit facilities. The proceeds of the new Term Loan B, together with the proceeds from the offering of $500.0 million aggregate principal amount of 5.75% senior notes (the “Original Notes” and, together with the Additional Notes, the “Notes”) and cash, were used to repay LPLH’s then-existing senior secured credit facilities and to pay accrued interest and related fees and expenses. The refinancing led to the extinguishment of the previous Term Loan A and B facilities, which required the Company to accelerate the recognition of $21.1 million of related unamortized debt issuance costs, and recognize that amount as a loss on extinguishment of debt in the consolidated statements of income. Issuance of 5.75% Senior Notes due 2025 The Original Notes were issued in March 2017 pursuant to an indenture, dated March 10, 2017, among LPLH, U.S. Bank National Association, as trustee, and certain of the Company’s subsidiaries as guarantors (as supplemented, the “Indenture”). The Additional Notes were issued in September 2017 pursuant to a supplemental indenture, dated September 21, 2017, among LPLH, U.S. Bank National Association, as trustee, and certain of the Company’s subsidiaries as guarantors. The Notes are unsecured obligations, will mature on September 15, 2025, and bear interest at the rate of 5.75% per year, with interest payable semi-annually, beginning on September 15, 2017 with respect to the Additional Notes. The Company may redeem all or part of the Notes at any time prior to March 15, 2020 (subject to a customary “equity claw” redemption right) at 100% of the principal amount redeemed plus a “make-whole” premium. Thereafter the Company may redeem all or part of the Notes at annually declining redemption premiums until March 15, 2023, at and after which date the redemption price will be equal to 100% of the principal amount redeemed. Senior Secured Credit Facilities Borrowings under the Term Loan B facility bear interest at a rate per annum of 225 basis points over the Eurodollar Rate or 125 basis point over the base rate (as defined in the Credit Agreement), and have no leverage or interest coverage maintenance covenants. Borrowings under the revolving credit facility bear interest at a rate per annum ranging from 125 to 175 basis points over the Eurodollar Rate or 25 to 75 basis points over the base rate, depending on the Consolidated Secured Debt to Consolidated EBITDA Ratio (as defined in the Credit Agreement). The Eurodollar Rate option is the one-, two-, three-, or six-month LIBOR rate, as selected by LPLH, or, with the approval of the applicable lenders, twelve month LIBOR rate or the LIBOR rate for another period acceptable to the Administrative Agent (including a shorter period). The Eurodollar Rate is subject to an interest rate floor of 0% . The Company’s outstanding borrowings were as follows (dollars in thousands): December 31, 2017 Long-Term Borrowings Current Applicable Margin Interest Rate Maturity Revolving Credit Facility $ — LIBOR+125bps — 9/21/2022 Senior Secured Term Loan B (1) 1,496,250 LIBOR+225 bps 3.81 % 9/21/2024 Senior Unsecured Notes (1)(2) 900,000 Fixed Rate 5.75 % 9/15/2025 Total long-term borrowings 2,396,250 Plus: Unamortized Premium 11,584 Less: Unamortized Debt Issuance Cost (22,812 ) Net Carrying Value $ 2,385,022 _____________________ (1) No leverage or interest coverage maintenance covenants. (2) The Senior Unsecured Notes were issued in two separate transactions; $500.0 million in Original Notes were issued in March 2017 at par; the remaining $400.0 million in Additional Notes were issued in September 2017 and priced at 103.0% of the aggregate principal amount. December 31, 2016 Senior Secured Credit Facilities Balance Interest Rate Maturity Term Loan A $ 459,375 3.27 % 9/30/2019 2019 Term Loan B 420,309 3.25 % 3/29/2019 2021 Term Loan B 624,676 4.25 % 3/29/2021 2022 Term Loan B 693,000 4.80 % 11/20/2022 Total borrowings 2,197,360 Less: Unamortized Debt Issuance Cost (21,924 ) Net Carrying Value $ 2,175,436 The Company is required to make quarterly payments on the Term Loan B facility (commencing with the fiscal quarter ending December 31, 2017), each equal to 0.25% of the original principal amount of the loans under the Term Loan B facility. Voluntary prepayments of the Term Loan B facility in connection with a Repricing Transaction (as defined in the Credit Agreement) on or prior to six months after the date of the Amendment will be subject to a call premium of 1.0% . Otherwise, outstanding loans under the Term Loan B facility may be voluntarily prepaid at any time without premium or penalty. As of December 31, 2017 , the Company had $11.1 million of irrevocable letters of credit, with an applicable interest rate margin of 1.25% , which were supported by the credit facility. The Credit Agreement subjects the Company to certain financial and non-financial covenants. As of December 31, 2017 , the Company was in compliance with such covenants. Bank Loans Payable The Company maintains three uncommitted lines of credit. Two of the lines have unspecified limits, which are primarily dependent on the Company’s ability to provide sufficient collateral. The third line has a $200.0 million limit and allows for both collateralized and uncollateralized borrowings. During the year ended December 31, 2017 , the Company drew a total of $239.0 million on one of the lines of credit at a weighted average interest rate of 2.61% . During the year ended December 31, 2016 , the Company drew $105.0 million on one of the lines of credit at an interest rate of 1.59% . The lines were not otherwise utilized in 2017 and 2016 . There were no balances outstanding at December 31, 2017 or 2016 . The minimum calendar year payments and maturities of the long-term borrowings as of December 31, 2017 are as follows (in thousands): 2018 $ 14,906 2019 14,758 2020 14,611 2021 14,465 2022 14,322 Thereafter 2,323,188 Total $ 2,396,250

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s provision for income taxes was as follows (in thousands): December 31, 2017 2016 2015 Current provision: Federal $ 117,745 $ 102,133 $ 123,633 State 17,353 15,002 20,291 Total current provision 135,098 117,135 143,924 Deferred benefit: Federal (8,951 ) (10,767 ) (24,972 ) State (440 ) (783 ) (5,181 ) Total deferred benefit (9,391 ) (11,550 ) (30,153 ) Provision for income taxes $ 125,707 $ 105,585 $ 113,771 A reconciliation of the United States federal statutory income tax rates to the Company’s effective income tax rates is set forth below: Years Ended December 31, 2017 2016 2015 Federal statutory income tax rates 35.0 % 35.0 % 35.0 % State income taxes, net of federal benefit 3.0 3.5 3.6 Non-deductible expenses 0.6 0.3 0.7 Share-based compensation (0.9 ) 0.1 — Tax Cuts and Jobs Act of 2017 (2.4 ) — — Domestic production activities deduction (0.9 ) (2.2 ) — Research & development credits (0.4 ) (1.1 ) — Other 0.5 (0.1 ) 1.0 Effective income tax rates 34.5 % 35.5 % 40.3 % The decrease in the Company's effective income tax rate and income tax expense in 2017 compared to 2016 was primarily due to tax benefits associated with the adoption of ASU 2016-09, Improvements to Employee Share-Based Payment Accounting , on January 1, 2017, and the revaluation of its deferred tax assets and liabilities under the Tax Cuts and Jobs Act 2017, partially offset by tax benefits recorded during 2016 associated with internally developed software that was not repeated in 2017. The decrease in the Company's effective income tax rate and income tax expense in 2016 compared to 2015 was primarily due to tax benefits associated with internally developed software that we determined in 2016. The components of the net deferred income taxes included in the consolidated statements of financial condition were as follows (in thousands): December 31, 2017 2016 Deferred tax assets: Accrued liabilities $ 59,422 $ 75,907 Share-based compensation 17,122 31,715 State taxes 5,630 9,345 Deferred rent 32,457 49,544 Provision for bad debts 2,956 7,520 Net operating losses — (10 ) Forgivable loans 7,643 9,381 Captive insurance 1,355 1,689 Other — 956 Total deferred tax assets 126,585 186,047 Deferred tax liabilities: Amortization of intangible assets (75,043 ) (122,482 ) Depreciation of fixed assets (63,213 ) (88,960 ) Other (4,333 ) (219 ) Total deferred tax liabilities (142,589 ) (211,661 ) Deferred income taxes, net $ (16,004 ) $ (25,614 ) The following table reflects a reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits, including interest and penalties (in thousands): December 31, 2017 2016 2015 Balance — Beginning of year $ 39,766 $ 24,747 $ 20,987 Increases for tax positions taken during the current year 7,815 17,787 4,404 Reductions as a result of a lapse of the applicable statute of limitations (4,924 ) (2,768 ) (644 ) Balance — End of year $ 42,657 $ 39,766 $ 24,747 At December 31, 2017 and 2016 , there were $37.6 million and $31.4 million , respectively, of unrecognized tax benefits that if recognized, would favorably affect the effective income tax rate in any future periods. The Company accrues interest and penalties related to unrecognized tax benefits in its provision for income taxes within the consolidated statements of financial condition. At December 31, 2017 and 2016 , the liability for unrecognized tax benefits included accrued interest of $4.5 million and $3.9 million , respectively, and penalties of $4.4 million and $4.5 million , respectively. The Company and its subsidiaries file income tax returns in the federal jurisdiction, as well as most state jurisdictions, and are subject to routine examinations by the respective taxing authorities. The Company has concluded all federal income tax matters for years through 2011 and all state income tax matters for years through 2006. The tax years of 2012 to 2016 remain open to examination in the federal jurisdiction. The tax years of 2007 to 2016 remain open to examination in the state jurisdictions. In the next 12 months, it is reasonably possible that the Company expects a reduction in unrecognized tax benefits of $2.7 million

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases The Company leases office space and equipment under various operating leases. These leases are generally subject to scheduled base rent and maintenance cost increases, which are recognized on a straight-line basis over the period of the leases. Total rental expense for all operating leases was approximately $20.1 million , $24.7 million , and $25.6 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively. Service and Development Contracts The Company is party to certain long-term contracts for systems and services that enable back office trade processing and clearing for its product and service offerings. Future minimum payments under leases, lease commitments, service, development, and agency contracts, and other contractual obligations with initial terms greater than one year were as follows at December 31, 2017 (in thousands): 2018 $ 63,430 2019 46,463 2020 35,057 2021 32,416 2022 32,741 Thereafter 270,252 Total(1) $ 480,359 _____________________ (1) Future minimum payments have not been reduced by minimum sublease rental income of $14.2 million due in the future under noncancellable subleases. Guarantees The Company occasionally enters into certain types of contracts that contingently require it to indemnify certain parties against third-party claims. The terms of these obligations vary and, because a maximum obligation is not explicitly stated, the Company has determined that it is not possible to make an estimate of the amount that it could be obligated to pay under such contracts. The Company’s subsidiary, LPL Financial, provides guarantees to securities clearing houses and exchanges under their standard membership agreements, which require a member to guarantee the performance of other members. Under these agreements, if a member becomes unable to satisfy its obligations to the clearing houses and exchanges, all other members would be required to meet any shortfall. The Company’s liability under these arrangements is not quantifiable and may exceed the cash and securities it has posted as collateral. However, the potential requirement for the Company to make payments under these agreements is remote. Accordingly, no liability has been recognized for these transactions. Loan Commitments From time to time, LPL Financial makes loans to its advisors, primarily to newly recruited advisors to assist in the transition process, which may be forgivable. Due to timing differences, LPL Financial may make commitments to issue such loans prior to actually funding them. These commitments are generally contingent upon certain events occurring, including but not limited to the advisor joining LPL Financial. LPL Financial had no significant unfunded commitments at December 31, 2017 . Legal & Regulatory Matters The Company is subject to extensive regulation and supervision by United States federal and state agencies and various self-regulatory organizations. The Company and its advisors periodically engage with such agencies and organizations, in the context of examinations or otherwise, to respond to inquiries, informational requests, and investigations. From time to time, such engagements result in regulatory complaints or other matters, the resolution of which has in the past and may in the future include fines, customer restitution and other remediation. Assessing the probability of a loss occurring and the amount of any loss related to a legal proceeding or regulatory matter is inherently difficult. While the Company exercises significant and complex judgments to make certain estimates presented in its consolidated financial statements, there are particular uncertainties and complexities involved when assessing the potential outcomes of legal proceedings and regulatory matters. The Company's assessment process considers a variety of factors and assumptions, which may include the procedural status of the matter and any recent developments; prior experience and the experience of others in similar matters; the size and nature of potential exposures; available defenses; the progress of fact discovery; the opinions of counsel and experts; potential opportunities for settlement and the status of any settlement discussions; as well as the potential for insurance coverage and indemnification, if available. The Company monitors these factors and assumptions for new developments and re-assesses the likelihood that a loss will occur and the estimated range or amount of loss, if those amounts can be reasonably determined. The Company has established an accrual for those legal proceedings and regulatory matters for which a loss is both probable and the amount can be reasonably estimated, except as otherwise covered by third-party insurance or self-insurance through the captive insurance subsidiary, as discussed below. A putative class action lawsuit has been filed against the Company and certain of its executive officers in federal district court alleging certain misstatements and omissions related to the Company’s share repurchases and financial performance in late 2015. Third-Party Insurance The Company maintains third-party insurance coverage for certain potential legal proceedings, including those involving certain client claims. With respect to such client claims, the estimated losses on many of the pending matters are less than the applicable deductibles of the insurance policies. Self-Insurance The Company has self-insurance for certain potential liabilities, including various errors and omissions liabilities, through a wholly-owned captive insurance subsidiary. Liabilities associated with the risks that are retained by the Company are not discounted and are estimated by considering, in part, historical claims experience, severity factors, and other actuarial assumptions. The estimated accruals for these potential liabilities could be significantly affected if future occurrences and claims differ from such assumptions and historical trends. As of December 31, 2017 and 2016 , these self-insurance liabilities are included in accounts payable and accrued liabilities in the consolidated statements of financial condition. Self-insurance related charges are included in other expenses in the consolidated statements of income for the years ended December 31, 2017 , 2016 , and 2015 . Other Commitments As of December 31, 2017 , the Company had approximately $270.9 million of client margin loans that were collateralized with securities having a fair value of approximately $379.2 million that it can repledge, loan, or sell. Of these securities, approximately $49.9 million were client-owned securities pledged to the Options Clearing Corporation as collateral to secure client obligations related to options positions. As of December 31, 2017 there were no restrictions that materially limited the Company's ability to repledge, loan, or sell the remaining $329.3 million of client collateral. Trading securities on the consolidated statements of financial condition includes $6.5 million and $3.0 million pledged to clearing organizations at December 31, 2017 and 2016

Stockholders' Equity Stockholde

Stockholders' Equity Stockholders' Equity (Notes)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders' Equity Dividends The payment, timing and amount of any dividends are subject to approval by the Company's board of directors (the "Board of Directors") as well as certain limits under the Credit Agreement and Indenture. Cash dividends per share of common stock and total cash dividends paid on a quarterly basis were as follows (in millions, except per share data): 2017 2016 Dividend per Share Total Cash Dividend Dividend per Share Total Cash Dividend First quarter $ 0.25 $ 22.6 $ 0.25 $ 22.2 Second quarter $ 0.25 $ 22.6 $ 0.25 $ 22.3 Third quarter $ 0.25 $ 22.5 $ 0.25 $ 22.3 Fourth quarter $ 0.25 $ 22.5 $ 0.25 $ 22.3 Share Repurchases The Company engages in share repurchase programs, which are approved by the Board of Directors, pursuant to which the Company may repurchase its issued and outstanding shares of common stock from time to time. Repurchased shares are included in treasury stock on the consolidated statements of financial condition. On December 5, 2017, the Board of Directors authorized an increase to the Company’s existing share repurchase program, enabling the Company to repurchase its issued and outstanding common stock from time to time. As of December 31, 2017 , the Company had $500.0 million remaining under the existing share repurchase program. Future share repurchases may be effected in open market or privately negotiated transactions, including transactions with affiliates, with the timing of purchases and the amount of stock purchased generally determined at the discretion of the Company within the constraints of the Credit Agreement, the Indenture, and the Company’s general working capital needs. The Company had the following activity under its approved share repurchase programs (in millions, except share and per share data): 2017 Total Number of Shares Purchased Weighted-Average Price Paid Per Share Total Cost(1) First Quarter 566,798 $ 39.68 $ 22.5 Second Quarter 910,349 $ 39.78 36.2 Third Quarter 539,385 $ 46.37 25.0 Fourth Quarter 603,000 $ 49.76 30.0 2,619,532 $ 43.42 $ 113.7 _________________________ (1) Included in the total cost of shares purchased is a commission fee of $0.02

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation Certain employees, advisors, institutions, officers, and directors of the Company participate in various long-term incentive plans, which provide for granting stock options, warrants, restricted stock awards, restricted stock units, deferred stock units and performance stock units. In November 2010, the Company adopted the 2010 Omnibus Equity Incentive Plan (as amended and restated in May 2015, the “ 2010 Plan ” ), which provides for the granting of stock options, warrants, restricted stock awards, restricted stock units, deferred stock units, performance stock units, and other equity-based compensation. Since its adoption, awards have been and are only made out of the 2010 Plan. As of December 31, 2017 , there were 20,055,945 shares authorized for grant under the 2010 Plan. There were 7,287,382 shares reserved for exercise or conversion of outstanding awards granted, and 7,813,333 shares remaining available for future issuance, under the 2010 Plan as of December 31, 2017 . Stock Options and Warrants The following table presents the weighted-average assumptions used in the Black-Scholes valuation model by the Company in calculating the fair value of its employee and officer stock options that have been granted: Years Ended December 31, 2017 2016 2015 Expected life (in years) 5.43 5.26 5.30 Expected stock price volatility 35.27 % 33.38 % 25.78 % Expected dividend yield 2.61 % 2.87 % 2.30 % Risk-free interest rate 2.14 % 1.16 % 1.58 % Fair value of options $ 10.63 $ 4.60 $ 8.81 The fair value of each stock option or warrant awarded to advisors and financial institutions is estimated on the date of grant and revalued at each reporting period using the Black-Scholes valuation model with the following weighted-average assumptions used: Years Ended December 31, 2017 2016 2015 Expected life (in years) 5.00 5.90 5.25 Expected stock price volatility 35.34 % 35.19 % 25.91 % Expected dividend yield 2.00 % 2.87 % 2.35 % Risk-free interest rate 2.14 % 2.13 % 1.84 % Fair value of options $ 24.93 $ 11.72 $ 12.12 The following table summarizes the Company’s stock option and warrant activity as of and for the year ended December 31, 2017 : Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (In thousands) Outstanding — December 31, 2016 7,153,982 $ 30.40 Granted 851,810 $ 39.48 Exercised (2,727,774 ) $ 30.17 Forfeited and Expired (411,519 ) $ 34.83 Outstanding — December 31, 2017 4,866,499 $ 31.73 5.87 $ 123,636 Exercisable — December 31, 2017 3,068,227 $ 32.29 4.32 $ 76,245 Exercisable and expected to vest — December 31, 2017 4,788,088 $ 31.69 5.82 $ 121,869 The following table summarizes information about outstanding stock options and warrants as of December 31, 2017 : Outstanding Exercisable Range of Exercise Prices Total Number of Shares Weighted- Average Remaining Life (Years) Weighted- Average Exercise Price Number of Shares Weighted- Average Exercise Price $18.04 - $23.02 1,642,309 5.96 $ 20.31 818,587 $ 20.78 $23.41 - $30.00 770,107 3.75 $ 28.16 734,811 $ 28.31 $31.60 - $32.33 408,375 4.66 $ 31.86 408,375 $ 31.86 $34.00 - $39.60 1,247,074 6.89 $ 37.56 481,722 $ 34.50 $42.59 - $54.81 798,634 6.76 $ 49.52 624,732 $ 50.64 4,866,499 5.87 $ 31.73 3,068,227 $ 32.29 The Company recognized share-based compensation related to the vesting of stock options awarded to employees and officers of $7.2 million , $10.7 million , and $14.5 million during the years ended December 31, 2017 , 2016 , and 2015 , respectively. As of December 31, 2017 , total unrecognized compensation cost related to non-vested stock options granted to employees and officers was $7.8 million , which is expected to be recognized over a weighted-average period of 1.83 years. During 2011 and 2012, the Company granted stock options and warrants to its advisors and financial institutions. The Company recognized share based compensation of $1.8 million , $1.8 million , and $3.4 million during the years ended December 31, 2017 , 2016 , and 2015 , respectively, related to the vesting of stock options and warrants awarded to its advisors and financial institutions. As of December 31, 2017 , all stock options and warrants granted to advisors and financial institutions were fully vested and the related compensation cost was fully recognized. Restricted Stock and Stock Units The following summarizes the Company’s activity in its restricted stock awards and stock units, which include restricted stock units, deferred stock units, and performance stock units, for the year ended December 31, 2017 : Restricted Stock Awards Stock Units Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Nonvested — December 31, 2016 10,404 $ 35.85 982,253 $ 30.61 Granted 18,700 $ 39.73 470,063 $ 40.10 Vested (16,308 ) $ 37.25 (385,999 ) $ 36.33 Forfeited — $ — (109,194 ) $ 31.92 Nonvested — December 31, 2017 12,796 $ 39.73 957,123 $ 32.81 Expected to vest — December 31, 2017 12,796 $ 39.73 902,829 $ 32.52 The Company grants restricted stock awards and deferred stock units to its directors, restricted stock units to its employees and officers and performance stock units to its officers. Restricted stock awards and stock units must vest or else are subject to forfeiture; however, restricted stock awards are included in our shares outstanding upon grant and have the same dividend and voting rights as our common stock. The Company recognized $11.5 million , $8.9 million , and $8.3 million of share-based compensation related to the vesting of these restricted stock awards, restricted stock units, deferred stock units, and performance stock units during the years ended December 31, 2017 , 2016 , and 2015 , respectively. As of December 31, 2017 , total unrecognized compensation cost for restricted stock awards, deferred stock units, restricted stock units and performance stock units was $13.0 million , which is expected to be recognized over a weighted-average remaining period of 1.94 years. The Company also grants restricted stock units to its advisors and to financial institutions. The Company recognized share-based compensation of $7.3 million , $2.7 million and $2.5 million related to the vesting of these awards during the years ended December 31, 2017 , 2016 , and 2015 respectively. As of December 31, 2017 , total unrecognized compensation cost for restricted stock units granted to advisors and financial institutions was $6.4 million , which is expected to be recognized over a weighted-average remaining period of 1.68

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share Basic earnings per share is computed by dividing net income available to common stockholders by the weighted-average number of shares of common stock outstanding during the period. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased to include the number of additional shares of common stock that would have been outstanding if dilutive potential shares of common stock had been issued. The calculation of basic and diluted earnings per share for the years noted was as follows (in thousands, except per share data): Years Ended December 31, 2017 2016 2015 Net income $ 238,863 $ 191,931 $ 168,784 Basic weighted-average number of shares outstanding 90,002 89,072 95,273 Dilutive common share equivalents 2,113 941 1,513 Diluted weighted-average number of shares outstanding 92,115 90,013 96,786 Basic earnings per share $ 2.65 $ 2.15 $ 1.77 Diluted earnings per share $ 2.59 $ 2.13 $ 1.74 The computation of diluted earnings per share excludes stock options, warrants, and stock units that are anti-dilutive. For the years ended December 31, 2017 , 2016 , and 2015 , stock options, warrants, and stock units representing common share equivalents of 1,909,288 shares, 4,054,972 shares, and 2,223,886

Employee and Advisor Benefit Pl

Employee and Advisor Benefit Plans	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Employee and Advisor Benefit Plans	Employee and Advisor Benefit Plans The Company participates in a 401(k) defined contribution plan sponsored by LPL Financial. All employees meeting minimum age and length of service requirements are eligible to participate. The Company has an employer matching program whereby employer contributions are made to the 401(k) plan, and employees are eligible for matching contributions after completing one year of service. The Company's contributions were made during the year ended December 31, 2017 in an amount equal to 65% of the first 8% of an employee's designated deferral of their eligible compensation. The Company’s total cost related to the 401(k) plan was $10.5 million , $10.1 million , and $9.9 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively, which is classified as compensation and benefits expense in the consolidated statements of income. In August 2012, the Company established the 2012 Employee Stock Purchase Plan (the “ ESPP ” ) as a benefit to enable eligible employees to purchase common stock of LPLFH at a discount from the market price through payroll deductions, subject to limitations. Eligible employees may elect to participate in the ESPP only during an open enrollment period. The offering period immediately follows the open enrollment window, upon which time ESPP contributions are withheld from the participant's regular paycheck. The ESPP provides for a 15% discount on the market value of the stock at the lower of the grant date price (first day of the offering period) and the purchase date price (last day of the offering period). In January 2008, the Company adopted a non-qualified deferred compensation plan for the purpose of attracting and retaining advisors who operate, for tax purposes, as independent contractors, by providing an opportunity for participating advisors to defer receipt of a portion of their gross commissions generated primarily from commissions earned on the sale of various products. The deferred compensation plan has been fully funded to date by participant contributions. Plan assets are invested in mutual funds, which are held by the Company in a Rabbi Trust. The liability for benefits accrued under the non-qualified deferred compensation plan totaled $177.7 million at December 31, 2017 , which is included in accounts payable and accrued liabilities in the consolidated statements of financial condition. The cash values of the related trust assets was $176.9 million at December 31, 2017 , which is measured at fair value and included in other assets in the consolidated statements of financial condition. Certain employees and advisors of the Company’s subsidiaries participated in non-qualified deferred compensation plans (the “ Plans ” ) that permitted participants to defer portions of their compensation and earn interest on the deferred amounts. The Plans were closed to new participants as of December 31, 2017 and no contributions have been made since the date of the Company's acquisition of such subsidiary. Plan assets are held by the Company in a Rabbi Trust and accounted for in the manner described above. As of December 31, 2017 , the Company has recorded assets of $3.5 million and liabilities of $1.8 million

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company has related party transactions with certain beneficial owners of more than ten percent of the Company's outstanding common stock. Additionally, through its subsidiary LPL Financial, the Company provides services and charitable contributions to the LPL Financial Foundation, an organization that provides volunteer and financial support within the Company's local communities. During the years ended December 31, 2017 , 2016 , and 2015 , the Company recognized revenue for services provided to these related parties of $3.1 million , $0.1 million , and $0.6 million , respectively. The Company incurred expenses for the services provided by these related parties of $1.9 million , $1.5 million , and $6.8 million , during the years ended December 31, 2017 , 2016 , and 2015 respectively. As of December 31, 2017 and 2016 , receivables and payables to related parties were not material. During the years ended December 31, 2016 and 2015 , the Company had related party transactions with certain portfolio companies of TPG Capital. TPG Capital was a shareholder of the Company's common stock and a firm of which one of the Company's directors previously served as a partner. For the year ended December 31, 2017

Net Capital and Regulatory Requ

Net Capital and Regulatory Requirements	12 Months Ended
	Dec. 31, 2017
Brokers and Dealers [Abstract]
Net Capital and Regulatory Requirements	Net Capital and Regulatory Requirements The Company’s registered broker-dealer, LPL Financial, is subject to the SEC’s Net Capital Rule (Rule 15c3-1 under the Exchange Act), which requires the maintenance of minimum net capital, as defined. Under the alternative method permitted by the rules, LPL Financial must maintain minimum net capital equal to the greater of $250,000 or 2% of aggregate debit items arising from client transactions. The net capital rules also provide that the broker-dealer's capital may not be withdrawn if resulting net capital would be less than minimum requirements. Additionally, certain withdrawals require the approval of the SEC and FINRA to the extent they exceed defined levels, even though such withdrawals would not cause net capital to be less than minimum requirements. Net capital and the related net capital requirement may fluctuate on a daily basis. LPL Financial is a clearing broker-dealer and, as of December 31, 2017 , had net capital of $99.5 million with a minimum net capital requirement of $7.8 million . The Company's subsidiary, PTC, also operates in a highly regulated industry and is subject to various regulatory capital requirements. Failure to meet minimum capital requirements can initiate certain mandatory and possible additional discretionary actions by regulators that if undertaken, could have substantial monetary and non-monetary impacts to PTC's operations. As of December 31, 2017 and 2016

Financial Instruments with Off-

Financial Instruments with Off-Balance-Sheet Credit Risk and Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2017
Concentration Risk Credit Risk Financial Instruments Off Balance Sheet Risk [Abstract]
Financial Instruments with Off-Balance-Sheet Credit Risk and Concentrations of Credit Risk	Financial Instruments with Off-Balance-Sheet Credit Risk and Concentrations of Credit Risk LPL Financial’s client securities activities are transacted on either a cash or margin basis. In margin transactions, LPL Financial extends credit to the advisor's client, subject to various regulatory and internal margin requirements, collateralized by cash and securities in the client’s account. As clients write options contracts or sell securities short, LPL Financial may incur losses if the clients do not fulfill their obligations and the collateral in the clients’ accounts is not sufficient to fully cover losses that clients may incur from these strategies. To control this risk, LPL Financial monitors margin levels daily and clients are required to deposit additional collateral, or reduce positions, when necessary. LPL Financial is obligated to settle transactions with brokers and other financial institutions even if its advisors' clients fail to meet their obligation to LPL Financial. Clients are required to complete their transactions on the settlement date, generally two business days after the trade date. If clients do not fulfill their contractual obligations, LPL Financial may incur losses. In addition, the Company occasionally enters into certain types of contracts to fulfill its sale of when, as, and if issued securities. When, as, and if issued securities have been authorized but are contingent upon the actual issuance of the security. LPL Financial has established procedures to reduce this risk by generally requiring that clients deposit cash or securities into their account prior to placing an order.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) 2017 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net revenues $ 1,035,427 $ 1,065,504 $ 1,064,108 $ 1,116,442 Net income $ 48,189 $ 68,434 $ 58,142 $ 64,098 Basic earnings per share $ 0.54 $ 0.76 $ 0.65 $ 0.71 Diluted earnings per share $ 0.52 $ 0.74 $ 0.63 $ 0.69 Dividends declared per share $ 0.25 $ 0.25 $ 0.25 $ 0.25 2016 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net revenues $ 1,005,305 $ 1,019,181 $ 1,017,440 $ 1,007,457 Net income $ 50,392 $ 47,849 $ 51,954 $ 41,736 Basic earnings per share $ 0.57 $ 0.54 $ 0.58 $ 0.47 Diluted earnings per share $ 0.56 $ 0.53 $ 0.58 $ 0.46 Dividends declared per share $ 0.25 $ 0.25 $ 0.25 $ 0.25

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Event On February 16, 2018 , the Board of Directors declared a cash dividend of $0.25 per share on the Company's outstanding common stock to be paid on March 23, 2018 to all stockholders of record on March 9, 2018

Summary of Significant Accoun30

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation These consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States ( “ GAAP ”
Reclassification, Policy [Policy Text Block]	.
Consolidation	Consolidation These consolidated financial statements include the accounts of LPLFH and its subsidiaries. Intercompany transactions and balances have been eliminated. Equity investments over which the Company exercises significant influence, but does not exercise control and is not the primary beneficiary, are accounted for using the equity method.
Reportable Segment	Reportable Segment Management has determined that the Company operates in one segment, given the similarities in economic characteristics between its operations and the common nature of its products and services, production and distribution process, and regulatory environment.
Revenue Recognition	Revenue Recognition Substantially all of the Company's revenues are based on contractual arrangements. In determining the appropriate recognition of commissions, the Company reviews the terms and conditions of the brokerage account agreements between the Company and its advisors' clients, representative agreements with its advisors, which include payout rates and terms, and selling agreements with product sponsors for packaged investment products such as mutual funds, annuities, insurance, and alternative investments. In determining the appropriate recognition of advisory revenues, the Company reviews the terms and conditions of the advisory agreements between the advisors' clients and the applicable registered investment advisor ( “ RIA ” ), representative agreements with its advisors, and agreements with third parties who provide specific investment management or investment strategies. Revenues are recognized in the periods in which the related services are performed provided that persuasive evidence of an arrangement exists, the fee is fixed or determinable, and collectability is reasonably assured. Payments received by the Company in advance of the performance of service are deferred and recognized as revenue when earned. Management considers the nature of the Company's contractual arrangements in determining whether to recognize certain types of revenue on the basis of the gross amount billed or net amount retained after payments are made to providers of certain services related to the product or service offering. The main factors the Company uses to determine whether to record revenue on a gross or net basis are whether: • the Company is primarily responsible for the service to the advisor and their client; • the Company has discretion in establishing fees paid by the client and fees due to the third-party service provider; and • the Company is involved in the determination of product or service specifications. When client fees include a portion of charges that are paid to another party and the Company is primarily responsible for providing the service to the client, revenue is recognized on a gross basis in an amount equal to the fee paid by the client. The cost of revenues recognized is the amount due to the other party and is recorded as commission and advisory expense in the consolidated statements of income. In instances in which another party is primarily responsible for providing the service to the client, revenue is recognized in the net amount retained by the Company. The portion of the fees that are collected from the client by the Company and remitted to the other party are considered pass-through amounts and accordingly are not a component of revenues or cost of revenues. Commission Revenues Commission revenues represent commissions generated by the Company's advisors for their clients' purchases and sales of securities on exchanges and over-the-counter, as well as purchases of various investment products such as mutual funds, variable and fixed annuities, alternative investments including non-traded real estate investment trusts and business development companies, fixed income, insurance, group annuities, and option and commodity transactions. The Company generates two types of commission revenues: transaction-based sales commissions that occur at the point of sale, as well as trailing commissions for which the Company provides ongoing support, awareness, and education to clients of its advisors. Transaction-based sales commissions are recognized as revenue on a trade-date basis, which is when the Company's performance obligations in generating the commissions have been substantially completed. The Company settles a significant volume of transactions that are initiated directly between its advisors and product sponsors, particularly with regard to mutual fund, 529 education savings plan, fixed and variable annuity, and insurance products. As a result, management must estimate a portion of its commission revenues earned from clients for purchases and sales of these products for each accounting period for which the proceeds have not yet been received. These estimates are based on the amount of commissions earned from transactions in these products in prior periods. Trailing commission revenues include mutual fund, 529 education savings plan, and fixed and variable product trailing fees that are recurring in nature. These trailing fees are earned by the Company based on a percentage of the current market value of clients' investment holdings in trail-eligible assets, and recognized over the period during which services are performed. Because trailing commission revenues are generally paid in arrears, management estimates the majority of trailing commission revenues earned during each period. These estimates are based on a number of factors, including market levels and the amount of trailing commission revenues received in prior periods. Commission revenue accruals are classified within receivables from product sponsors, broker-dealers, and clearing organizations in the consolidated statements of financial condition. A substantial portion of the commission revenue is ultimately paid to the advisors. The Company records an estimate for commissions payable based upon average payout ratios for each product for which the Company has accrued commission revenue. Such amounts are classified as accrued commission and advisory expenses payable in the consolidated statements of financial condition and commission and advisory expense in the consolidated statements of income. Advisory Revenues The Company records fees charged to clients as advisory revenues in advisory accounts where LPL Financial is the RIA firm. A substantial portion of these advisory fees are paid to the related advisor and these payments are classified as commission and advisory expense in the consolidated statements of income. Certain advisors conduct their advisory business through separate entities by establishing their own RIA firm pursuant to the Advisers Act or through their respective states' investment advisory licensing rules, rather than using the Company's corporate RIA platform. These independent entities, or Hybrid RIAs, engage the Company for clearing, regulatory, and custody services, including oversight of assets held at third-party custodians, as well as access to the Company's investment advisory platforms. The advisory revenue generated by these Hybrid RIAs is earned by the advisors, and accordingly not included in the Company's advisory revenues. The Company charges separate fees to Hybrid RIAs for technology, custody, administrative, and clearing services, primarily based on the value of assets within these advisory accounts, which are classified as advisory revenues in the consolidated statements of income. Asset-Based Revenues Asset-based revenues are comprised of fees from cash sweep programs, financial product manufacturer sponsorship programs, and omnibus processing and networking services and are recognized ratably over the period in which services are provided. Transaction and Fee Revenues The Company charges fees for executing certain transactions in client accounts. Transaction related charges are recognized on a trade-date basis. Other fees relate to services provided and other account charges generally outlined in agreements with clients, advisors, and financial institutions. Such fees are recognized as services are performed or as earned, as applicable. In addition, the Company offers various services for which fees are charged on a subscription basis and recognized over the subscription period. Interest Income, Net of Interest Expense The Company earns interest income from its cash equivalents and client margin balances, less interest expense on related transactions. Because interest expense incurred in connection with cash equivalents and client margin balances is completely offset by revenue on related transactions, the Company considers such interest to be an operating expense. Interest expense from operations for the years ended December 31, 2017 , 2016 , and 2015 did not exceed $1.0 million
Compensation and Benefits	Compensation and Benefits The Company records compensation and benefits expense for all cash and deferred compensation, benefits, and related taxes as earned by its employees. Compensation and benefits expense also includes fees earned by temporary employees and contractors who perform similar services to those performed by the Company’s employees, primarily software development and project management activities.
Share-Based Compensation	Share-Based Compensation Certain employees, officers, directors, advisors, and financial institutions of the Company participate in various long-term incentive plans that provide for granting stock options, warrants, restricted stock awards, restricted stock units, deferred stock units and performance stock units. Stock options, warrants and restricted stock units generally vest in equal increments over a three year period and expire on the tenth anniversary following the date of grant. Restricted stock awards and deferred stock units generally vest over a one year period, and performance stock units generally vest in full at the end of a three-year performance period. The Company recognizes share-based compensation for equity awards granted to employees, officers, and directors as compensation and benefits expense on the consolidated statements of income. The fair value of stock options is estimated using a Black-Scholes valuation model on the date of grant. The fair value of restricted stock awards, restricted stock units, and deferred stock units is equal to the closing price of the Company’s stock on the date of grant. The fair value of performance stock units is estimated using a Monte-Carlo simulation model on the date of grant. Share-based compensation is recognized over the requisite service period of the individual awards, which generally equals the vesting period. The Company recognizes share-based compensation for equity awards granted to advisors and financial institutions as commissions and advisory expense on the consolidated statements of income. The fair value of stock options and warrants is estimated using a Black-Scholes valuation model on the date of grant and is revalued at each reporting period. The fair value of restricted stock units is equal to the closing price of the Company’s stock on the date of grant and on the last day of each reporting period. Share-based compensation is recognized over the requisite service period of the individual awards, which generally equals the vesting period. The Company also makes assumptions regarding the number of stock options, warrants, restricted stock awards, restricted stock units, deferred stock units and performance stock units that will be forfeited. The forfeiture assumption is ultimately adjusted to the actual forfeiture rate. Therefore, changes in the forfeiture assumptions do not impact the total amount of expense ultimately recognized over the vesting period. Rather, different forfeiture assumptions would only impact the timing of expense recognition over the vesting period. See Note 14 . Share-Based Compensation
Earnings Per Share	Earnings Per Share Basic earnings per share is computed by dividing net income available to common shareholders by the basic weighted-average number of shares of common stock outstanding during the period. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased to include the number of additional shares of common stock that would have been outstanding if dilutive potential shares of common stock had been issued.
Income Taxes	Income Taxes In preparing the consolidated financial statements, the Company estimates income tax expense based on various jurisdictions where it conducts business. The Company then must assess the likelihood that the deferred tax assets will be realized. A valuation allowance is established to the extent that it is more-likely-than-not that such deferred tax assets will not be realized. When the Company establishes a valuation allowance or modifies the existing allowance in a certain reporting period, it generally records a corresponding increase or decrease to tax expense in the consolidated statements of income. Management makes significant judgments in determining the provision for income taxes, the deferred tax assets and liabilities, and any valuation allowances recorded against the deferred tax asset. Changes in the estimate of these taxes occur periodically due to changes in the tax rates, changes in the business operations, implementation of tax planning strategies, resolution with taxing authorities of issues where the Company had previously taken certain tax positions, and newly enacted statutory, judicial, and regulatory guidance. These changes could have a material effect on the Company’s consolidated statements of income, financial condition, or cash flows in the period or periods in which they occur. Income tax credits are accounted for using the flow-through method as a reduction of income tax in the years utilized. The Company recognizes the tax effects of a position in the consolidated financial statements only if it is more-likely-than-not to be sustained based solely on its technical merits; otherwise no benefits of the position are to be recognized. The more-likely-than-not threshold must continue to be met in each reporting period to support continued recognition of a benefit. Moreover, each tax position meeting the recognition threshold is required to
Cash and Cash Equivalents, Cash and Securities Segregated Under Federal and Other Regulations, Restricted Cash	Cash and Cash Equivalents Cash equivalents are highly liquid investments with an original maturity of 90 days or less that are not required to be segregated under federal or other regulations. The Company's cash and cash equivalents are composed of interest and noninterest-bearing deposits, money market funds, and United States government obligations. Cash and Securities Segregated Under Federal and Other Regulations The Company's subsidiary, LPL Financial, is subject to requirements related to maintaining cash or qualified securities in a segregated reserve account for the exclusive benefit of its customers in accordance with Rule 15c3-3 of the Security Exchange Act of 1934, as amended, and other regulations. Held within this account is approximately $100,000 for the proprietary accounts of introducing brokers. Restricted Cash
Receivable From and Payables to Clients	Receivables From and Payables to Clients Receivables from clients include amounts due on cash and margin transactions. The Company extends credit to clients of its advisors to finance their purchases of securities on margin and receives income from interest charged on such extensions of credit. Payables to clients represent credit balances in client accounts arising from deposits of funds, proceeds from sales of securities, and dividend and interest payments received on securities held in client accounts at LPL Financial. At December 31, 2017 and 2016 , $920.1 million and $836.6 million , respectively, of the balance represent free credit balances that are held pending re-investment by the clients. The Company pays interest on certain client payable balances.
Advisor Loans [Policy Text Block]	Advisor Loans The Company periodically extends credit to its advisors in the form of recruiting loans, commission advances, and other loans. The decisions to extend credit to advisors are generally based on the advisors’ credit history and their ability to generate future commissions. Certain loans made in connection with recruiting are forgivable over terms ranging from three to eight years provided that the advisor remains licensed through LPL Financial. At December 31, 2017 , $159.9 million
Receivables	Receivables From Others Receivables from others primarily consist of accrued fees from product sponsors and amounts due from advisors. Management maintains an allowance for uncollectible amounts using an aging analysis that takes into account the specific type of receivable. The aging thresholds and specific percentages used represent management’s best estimates of probable losses. Management monitors the adequacy of these estimates through periodic evaluations against actual trends experienced
Securities Owned and Securities Sold, But Not Yet Purchased	Securities Owned and Securities Sold, But Not Yet Purchased Securities owned and securities sold, but not yet purchased include trading and held-to-maturity securities. The Company generally classifies its investments in debt and equity instruments (including mutual funds, annuities, corporate bonds, government bonds, and municipal bonds) as trading securities, except for United States government notes held by PTC, which are classified as held-to-maturity securities. The Company has not classified any investments as available-for-sale. Investment classifications are subject to ongoing review and can change. Securities classified as trading are carried at fair value, while securities classified as held-to-maturity are carried at amortized cost. The Company uses prices obtained from independent third-party pricing services to measure the fair value of its trading securities. Prices received from the pricing services are validated using various methods including comparison to prices received from additional pricing services, comparison to available quoted market prices, and review of other relevant market data including implied yields of major categories of securities. In general, these quoted prices are derived from active markets for identical assets or liabilities. When quoted prices in active markets for identical assets and liabilities are not available, the quoted prices are based on similar assets and liabilities or inputs other than the quoted prices that are observable, either directly or indirectly. For certificates of deposit and treasury securities, the Company utilizes market-based inputs, including observable market interest rates that correspond to the remaining maturities or the next interest reset dates. At December 31, 2017 , the Company did not adjust prices received from the independent third-party pricing services. Interest income is accrued as earned. Premiums and discounts are amortized using a method that approximates the effective yield method over the term of the security and are recorded as an adjustment to the investment yield. The Company makes estimates about the fair value of investments and the timing for recognizing losses based on market conditions and other factors. If these estimates change, the Company may recognize
Securities Borrowed	Securities Borrowed The Company borrows securities from other broker-dealers to make deliveries or to facilitate customer short sales. Securities borrowed are accounted for as collateralized financings and are recorded at contract value, representing the amount of cash provided for securities borrowed transactions (generally in excess of market values). The adequacy of the collateral deposited, which is determined by comparing the market value of the securities borrowed to the cash loaned , is continuously monitored and is adjusted when considered necessary to minimize the risk associated with this activity. As of December 31, 2017 , the contract and collateral market values of borrowed securities were $12.5 million and $12.1 million , respectively. As of December 31, 2016 , the contract and collateral market values of borrowed securities were $5.6 million and $5.4 million
Fixed Assets	Fixed Assets Internally developed software, leasehold improvements, computers and software, and furniture and equipment are recorded at historical cost, net of accumulated depreciation and amortization. Depreciation is recognized using the straight-line method over the estimated useful lives of the assets. The Company charges software development costs to operations as incurred during the preliminary project stage, while capitalizing costs at the point at which the conceptual formulation, design, and testing of possible software project alternatives are complete and management authorizes and commits to funding the project. The costs of internally developed software that qualify for capitalization are capitalized as fixed assets and subsequently amortized over the estimated useful life of the software, which is generally three years. The Company does not capitalize pilot projects and projects for which it believes that the future economic benefits are less than probable. Leasehold improvements are amortized over the lesser of their useful lives or the terms of the underlying leases. Computers and software, as well as furniture and equipment, are depreciated over a period of three to seven years. Land is not depreciated. Management reviews fixed assets for impairment whenever events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. No material impairment occurred for the years ended December 31, 2017 , 2016 , and 2015
Business Combinations and Other Purchase of Business Transactions, Policy [Policy Text Block]	Acquisitions When acquiring companies, the Company recognizes separately from goodwill the assets acquired and the liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred and the net of the acquisition date fair values of the assets acquired and the liabilities assumed. While the Company uses its best estimates and assumptions as a part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the consolidated statements of income. Accounting for business combinations requires the Company's management to make significant estimates and assumptions, especially at the acquisition date with respect to intangible assets, support liabilities assumed, and pre-acquisition contingencies. These assumptions are based in part on historical experience, market data, and information obtained from the management of the acquired companies and are inherently uncertain.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill and other indefinite-lived assets are not amortized; however, intangible assets that are deemed to have definite lives are amortized over their useful lives, generally ranging from 5 - 20 years. See Note 8 . Goodwill and Other Intangible Assets , for additional information regarding the Company's goodwill and other intangible assets. Goodwill and other indefinite-lived intangible assets are tested annually for impairment in the fourth fiscal quarter and between annual tests if certain events occur indicating that the carrying amounts may be impaired. If a qualitative assessment is used and the Company determines that the fair value of a reporting unit or indefinite-lived intangible asset is more likely than not (i.e., a likelihood of more than 50%) less than its carrying amount, a quantitative impairment test will be performed. If goodwill or other indefinite-lived intangible assets are quantitatively assessed for impairment, a two-step approach is applied. For goodwill, the Company first compares the estimated fair value of the reporting unit in which the asset resides to its carrying value. For indefinite-lived intangible assets, the Company first compares the estimated fair value of the indefinite-lived intangible asset to its carrying value. The second step, if necessary, measures the amount of such impairment by comparing the implied fair value of the asset to its carrying value. No impairment of goodwill or other indefinite-lived intangible assets was recognized during the years ended December 31, 2017 , 2016 , or 2015 . Long-lived assets, such as intangible assets subject to amortization, are reviewed for impairment when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of an asset or asset group to estimated undiscounted future cash flows expected to be generated by the asset or asset group. If the carrying amount of an asset or asset group exceeds its estimated future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset or asset group exceeds the estimated fair value of the asset or asset group. Long-lived assets to be disposed of by sale are reported at the lower of their carrying amounts or their estimated fair values less costs to sell and are not depreciated. There was no material impairment of definite-lived intangible assets recognized during the years ended December 31, 2017 , 2016 , and 2015
Debt Issuance Costs	Debt Issuance Costs Debt issuance and amendment costs have been capitalized and are being amortized as additional interest expense over the expected terms of the related debt agreements. Debt issuance costs are presented as a direct deduction from the carrying amount of the related debt liability. Costs incurred while obtaining the revolving credit facility are included in other assets and subsequently amortized ratably over the term of the revolving credit facility, regardless of whether there are any outstanding borrowings on the revolving credit facility.
Fair Value of Debt Instruments	Fair Value of Financial Instruments The Company’s financial assets and liabilities are carried at fair value or at amounts that, because of their short-term nature, approximate current fair value, with the exception of its held-to-maturity securities and indebtedness, which are carried at amortized cost. The Company measures the implied fair value of its debt instruments using trading levels obtained from a third-party service provider. Accordingly, the debt instruments qualify as Level 2 fair value measurements. See Note 4 . Fair Value Measurements , for additional information regarding the Company's fair value measurements. As of December 31, 2017 , the carrying amount and fair value of the Company’s indebtedness was approximately $2,396.3 million and $2,422.0 million , respectively. As of December 31, 2016 , the carrying amount and fair value was approximately $2,197.4 million and $2,218.9 million
Commitments and Contingencies	Commitments and Contingencies The Company recognizes a liability with regard to loss contingencies when it believes it is probable a liability has occurred and the amount can be reasonably estimated. If some amount within a range of loss appears at the time to be a better estimate than any other amount within the range, the Company accrues that amount. When no amount within the range is a better estimate than any other amount, however, the Company accrues the minimum amount in the range.
Leasehold Financing Obligation Policy [Policy Text Block]	Leasehold Financing ObligationThe Company was involved in a build-to-suit lease arrangement in Fort Mill, South Carolina, under which it served as the construction agent on behalf of the landlord and bore substantially all of the risks and rewards of ownership as measured under GAAP. The Company was therefore required to report the landlord's costs of construction as a fixed asset during the construction period as if the Company owned such asset and an equal and off-setting leasehold financing obligation on our consolidated statements of financial condition. The construction was completed in October 2016 and it was determined that the asset did not qualify for sale-leaseback accounting treatment. As such, the Company accounts for this arrangement as a capital lease in which the asset is depreciated and the lease payments are recognized as a reduction of the financing obligation and interest expense over the lease term on our consolidated statements of income.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers: Topic 606 , to supersede nearly all existing revenue recognition guidance under GAAP. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers: Deferral of the Effective Date , which deferred the effective date for implementation of ASU 2014-09 by one year and is now effective for annual reporting periods beginning after December 15, 2017, with early adoption permitted but not earlier than the original effective date. ASU 2014-09 also requires new qualitative and quantitative disclosures, including disaggregation of revenues and descriptions of performance obligations. The Company adopted the provisions of this guidance on January 1, 2018 using the modified retrospective approach. The Company has performed an assessment of its revenue contracts as well as worked with industry participants on matters of interpretation and application and has not identified any material changes to the timing or amount of its revenue recognition under ASU 2014-09. The Company's accounting policies did not change materially as a result of applying the principles of revenue recognition from ASU 2014-09 and are largely consistent with existing guidance and current practices applied by the Company. The Company will provide additional disaggregation of revenue in accordance with ASU 2014-09. In February 2016, the FASB issued ASU 2016-02, Leases , which establishes a right-of-use model that requires a lessee to record a right-of-use asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the statement of operations. The Company expects to adopt the provisions of this guidance on January 1, 2019. The Company has identified the affected population of its leases and is evaluating the impact that ASU 2016-02 will have on its consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which clarifies how companies present and classify certain cash receipts and cash payments in the statement of cash flows. The Company adopted the provisions of this guidance on January 1, 2018, which must be applied using a retrospective transition method to each period presented. The adoption is not expected to have a material impact on its consolidated financial statements but will impact the presentation of the cash flow statement and the Company's disclosures. In November 2016, the FASB issued ASU 2016-18, Statements of Cash Flows (Topic 230): Classification and Presentation of Restricted Cash in the Statements of Cash Flows, which requires that restricted cash and restricted cash equivalents be included as components of total cash and cash equivalents in the statement of cash flows. The Company adopted the provisions of this guidance on January 1, 2018, and will begin presenting segregated cash and restricted cash activity on the consolidated statements of cash flows using a retrospective transition method for each period presented. In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment , which eliminates Step 2 from the goodwill impairment test and requires an entity to recognize an impairment charge for the amount by which the carrying amount of goodwill exceeds the reporting unit’s fair value, not to exceed the carrying amount of goodwill. The Company expects to adopt the provisions of this guidance on January 1, 2020. The adoption is not expected to have a material impact on the Company’s consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Scope of Modification Accounting (Topic 718) , which amends the scope of modification accounting for share-based payment arrangements. ASU 2017-09 provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under ASC 718. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions, and classification of the awards are the same immediately before and after the modification. The new standard is effective for annual periods beginning after December 15, 2017 and interim periods within those years. The Company does not expect a material impact from this update on its consolidated financial statements and related disclosures. Recently Adopted Accounting Pronouncements On January 1, 2017, the Company adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting . The ASU is designed to identify areas for simplification involving several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, an option to recognize gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. The adoption of ASU 2016-09 had no material impact on the Company's consolidated financial statements; however, it did reduce the Company's effective income tax rate for the twelve months ended December 31, 2017

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Schedule for uncollectible amounts due from clients	The following schedule reflects the Company’s activity in providing for an allowance for uncollectible amounts for advisor loans (in thousands): December 31, 2017 2016 Beginning balance — January 1 $ 1,852 $ 697 Provision for bad debts, net of recoveries 951 1,155 Charge-offs (2,914 ) — Reclassification from receivables from others 3,375 — Ending balance — December 31 $ 3,264 $ 1,852 December 31, 2017 2016 Beginning balance — January 1 $ 1,580 $ 1,464 Provision for bad debts, net of recoveries (15 ) 116 Charge-offs (1,099 ) — Ending balance — December 31 $ 466 $ 1,580 December 31, 2017 2016 Beginning balance — January 1 $ 12,851 $ 9,856 Provision for bad debts, net of recoveries 1,853 2,786 Charge-offs (5,214 ) 209 Reclassification to advisor loans (3,375 ) — Ending balance — December 31 $ 6,115 $ 12,851

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Financial assets and financial liabilities measured at fair value on a recurring basis	The following table summarizes the Company’s financial assets and financial liabilities measured at fair value on a recurring basis at December 31, 2017 (in thousands): Level 1 Level 2 Level 3 Total Assets Cash equivalents $ 147,034 $ — $ — $ 147,034 Securities owned — trading: Money market funds 288 — — 288 Mutual funds 10,850 — — 10,850 Equity securities 201 — — 201 Debt securities — 60 — 60 U.S. treasury obligations 6,480 — — 6,480 Total securities owned — trading 17,819 60 — 17,879 Other assets 180,377 9,282 — 189,659 Total assets at fair value $ 345,230 $ 9,342 $ — $ 354,572 Liabilities Securities sold, but not yet purchased: Mutual funds $ 3 $ — $ — $ 3 Equity securities 67 — — 67 Debt securities — 1,112 — 1,112 Total securities sold, but not yet purchased 70 1,112 — 1,182 Total liabilities at fair value $ 70 $ 1,112 $ — $ 1,182 The following table summarizes the Company’s financial assets and liabilities measured at fair value on a recurring basis at December 31, 2016 (in thousands): Level 1 Level 2 Level 3 Total Assets Cash equivalents $ 168,320 $ — $ — $ 168,320 Securities owned — trading: Money market funds 474 — — 474 Mutual funds 7,585 — — 7,585 Equity securities 35 — — 35 Debt securities — 314 — 314 U.S. treasury obligations 2,996 — — 2,996 Total securities owned — trading 11,090 314 — 11,404 Other assets 134,914 7,105 — 142,019 Total assets at fair value $ 314,324 $ 7,419 $ — $ 321,743 Liabilities Securities sold, but not yet purchased: Equity securities $ 168 $ — $ — $ 168 Debt securities — 15 — 15 Total securities sold, but not yet purchased 168 15 — 183 Accounts payable and accrued liabilities — 86 527 613 Total liabilities at fair value $ 168 $ 101 $ 527 $ 796

Held-to-Maturity Securities (Ta

Held-to-Maturity Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of amortized cost, gross unrealized loss, and fair value of securities held-to-maturity	The amortized cost, gross unrealized loss, and fair value of securities held-to-maturity were as follows (in thousands): December 31, 2017 2016 Amortized cost $ 11,833 $ 8,862 Gross unrealized loss (86 ) (31 ) Fair value $ 11,747 $ 8,831
Maturities of securities held-to-maturity	At December 31, 2017 , the securities held-to-maturity were scheduled to mature as follows (in thousands): Within one year After one but within five years After five but within ten years Total U.S. government notes — at amortized cost $ 5,006 $ 6,327 $ 500 $ 11,833 U.S. government notes — at fair value $ 4,986 $ 6,266 $ 495 $ 11,747

Receivables from Product Spon34

Receivables from Product Sponsors, Broker-Dealers and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations (Tables)	12 Months Ended
	Dec. 31, 2017
Due to and from Broker-Dealers and Clearing Organizations [Abstract]
Receivables from Product Sponsors, Broker-Dealers and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations	Receivables from product sponsors, broker-dealers, and clearing organizations and payables to broker-dealers and clearing organizations were as follows (in thousands): December 31, 2017 2016 Receivables: Commissions receivable from product sponsors and others $ 125,891 $ 116,218 Receivable from clearing organizations 62,561 50,656 Receivable from broker-dealers 1,389 1,309 Securities failed-to-deliver 6,366 6,939 Total receivables $ 196,207 $ 175,122 Payables: Payable to clearing organizations $ 13,316 $ 26,517 Payable to broker-dealers 31,869 32,065 Securities failed-to-receive 9,077 4,450 Total payables $ 54,262 $ 63,032

Fixed Assets (Tables)

Fixed Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
The components of fixed assets	The components of fixed assets were as follows (in thousands): December 31, 2017 2016 Internally developed software $ 346,029 $ 293,997 Leasehold improvements 82,413 86,171 Computers and software 160,400 122,442 Buildings 105,939 105,939 Furniture and equipment 73,767 74,492 Land 4,678 4,678 Construction in progress 66,802 55,568 Total fixed assets 840,028 743,287 Accumulated depreciation and amortization (427,344 ) (355,919 ) Fixed assets, net $ 412,684 $ 387,368

Goodwill and Other Intangible36

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of activity in goodwill	A summary of the activity in goodwill is presented below (in thousands): Balance at December 31, 2015 $ 1,365,838 Goodwill acquired — Balance at December 31, 2016 $ 1,365,838 Goodwill acquired 61,931 Balance at December 31, 2017 $ 1,427,769
Components of intangible assets	The components of intangible assets were as follows at December 31, 2017 (dollars in thousands): Weighted-Average Life Remaining (in years) Gross Carrying Value Accumulated Amortization Net Carrying Value Definite-lived intangible assets: Advisor and financial institution relationships 8.0 $ 538,921 $ (269,294 ) $ 269,627 Product sponsor relationships 8.1 234,086 (137,615 ) 96,471 Client relationships 6.8 19,133 (11,477 ) 7,656 Trade names 4.3 1,200 (680 ) 520 Total definite-lived intangible assets $ 793,340 $ (419,066 ) $ 374,274 Indefinite-lived intangible assets: Trademark and trade name 39,819 Total intangible assets $ 414,093 The components of intangible assets were as follows at December 31, 2016 (dollars in thousands): Weighted-Average Life Remaining (in years) Gross Carrying Value Accumulated Amortization Net Carrying Value Definite-lived intangible assets: Advisor and financial institution relationships 9.0 $ 440,533 $ (244,540 ) $ 195,993 Product sponsor relationships 9.1 234,086 (125,620 ) 108,466 Client relationships 7.7 19,133 (10,055 ) 9,078 Trade names 5.3 1,200 (560 ) 640 Total definite-lived intangible assets $ 694,952 $ (380,775 ) $ 314,177 Indefinite-lived intangible assets: Trademark and trade name 39,819 Total intangible assets $ 353,996
Amortization expense	ture amortization expense is estimated as follows (in thousands): 2018 $ 47,678 2019 47,642 2020 47,250 2021 47,093 2022 46,345 Thereafter 138,266 Total $ 374,274

Accounts Payable and Accrued 37

Accounts Payable and Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Summary of accounts payable and accrued liabilities	Accounts payable and accrued liabilities were as follows (in thousands): December 31, 2017 2016 Advisor deferred compensation plan liability $ 177,652 $ 133,632 Accrued compensation 64,728 63,741 Deferred rent 41,629 43,817 Accounts payable 47,125 23,284 Other accrued liabilities 130,015 121,071 Total accounts payable and accrued liabilities $ 461,149 $ 385,545

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Outstanding borrowings	The Company’s outstanding borrowings were as follows (dollars in thousands): December 31, 2017 Long-Term Borrowings Current Applicable Margin Interest Rate Maturity Revolving Credit Facility $ — LIBOR+125bps — 9/21/2022 Senior Secured Term Loan B (1) 1,496,250 LIBOR+225 bps 3.81 % 9/21/2024 Senior Unsecured Notes (1)(2) 900,000 Fixed Rate 5.75 % 9/15/2025 Total long-term borrowings 2,396,250 Plus: Unamortized Premium 11,584 Less: Unamortized Debt Issuance Cost (22,812 ) Net Carrying Value $ 2,385,022 _____________________ (1) No leverage or interest coverage maintenance covenants. (2) The Senior Unsecured Notes were issued in two separate transactions; $500.0 million in Original Notes were issued in March 2017 at par; the remaining $400.0 million in Additional Notes were issued in September 2017 and priced at 103.0% of the aggregate principal amount. December 31, 2016 Senior Secured Credit Facilities Balance Interest Rate Maturity Term Loan A $ 459,375 3.27 % 9/30/2019 2019 Term Loan B 420,309 3.25 % 3/29/2019 2021 Term Loan B 624,676 4.25 % 3/29/2021 2022 Term Loan B 693,000 4.80 % 11/20/2022 Total borrowings 2,197,360 Less: Unamortized Debt Issuance Cost (21,924 ) Net Carrying Value $ 2,175,436
Summary of minimum calendar year payments and maturities of the senior secured borrowings	The minimum calendar year payments and maturities of the long-term borrowings as of December 31, 2017 are as follows (in thousands): 2018 $ 14,906 2019 14,758 2020 14,611 2021 14,465 2022 14,322 Thereafter 2,323,188 Total $ 2,396,250

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Summary of provision for income taxes	The Company’s provision for income taxes was as follows (in thousands): December 31, 2017 2016 2015 Current provision: Federal $ 117,745 $ 102,133 $ 123,633 State 17,353 15,002 20,291 Total current provision 135,098 117,135 143,924 Deferred benefit: Federal (8,951 ) (10,767 ) (24,972 ) State (440 ) (783 ) (5,181 ) Total deferred benefit (9,391 ) (11,550 ) (30,153 ) Provision for income taxes $ 125,707 $ 105,585 $ 113,771
Summary of effective income tax rate reconciliation	A reconciliation of the United States federal statutory income tax rates to the Company’s effective income tax rates is set forth below: Years Ended December 31, 2017 2016 2015 Federal statutory income tax rates 35.0 % 35.0 % 35.0 % State income taxes, net of federal benefit 3.0 3.5 3.6 Non-deductible expenses 0.6 0.3 0.7 Share-based compensation (0.9 ) 0.1 — Tax Cuts and Jobs Act of 2017 (2.4 ) — — Domestic production activities deduction (0.9 ) (2.2 ) — Research & development credits (0.4 ) (1.1 ) — Other 0.5 (0.1 ) 1.0 Effective income tax rates 34.5 % 35.5 % 40.3 %
Components of the net deferred income taxes	The components of the net deferred income taxes included in the consolidated statements of financial condition were as follows (in thousands): December 31, 2017 2016 Deferred tax assets: Accrued liabilities $ 59,422 $ 75,907 Share-based compensation 17,122 31,715 State taxes 5,630 9,345 Deferred rent 32,457 49,544 Provision for bad debts 2,956 7,520 Net operating losses — (10 ) Forgivable loans 7,643 9,381 Captive insurance 1,355 1,689 Other — 956 Total deferred tax assets 126,585 186,047 Deferred tax liabilities: Amortization of intangible assets (75,043 ) (122,482 ) Depreciation of fixed assets (63,213 ) (88,960 ) Other (4,333 ) (219 ) Total deferred tax liabilities (142,589 ) (211,661 ) Deferred income taxes, net $ (16,004 ) $ (25,614 )
Summary of gross unrecognized tax benefits including interest and penalties reconciliation	The following table reflects a reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits, including interest and penalties (in thousands): December 31, 2017 2016 2015 Balance — Beginning of year $ 39,766 $ 24,747 $ 20,987 Increases for tax positions taken during the current year 7,815 17,787 4,404 Reductions as a result of a lapse of the applicable statute of limitations (4,924 ) (2,768 ) (644 ) Balance — End of year $ 42,657 $ 39,766 $ 24,747

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Future minimum payments	Future minimum payments under leases, lease commitments, service, development, and agency contracts, and other contractual obligations with initial terms greater than one year were as follows at December 31, 2017 (in thousands): 2018 $ 63,430 2019 46,463 2020 35,057 2021 32,416 2022 32,741 Thereafter 270,252 Total(1) $ 480,359 _____________________ (1) Future minimum payments have not been reduced by minimum sublease rental income of $14.2 million

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Schedule of dividends paid per common share	Cash dividends per share of common stock and total cash dividends paid on a quarterly basis were as follows (in millions, except per share data): 2017 2016 Dividend per Share Total Cash Dividend Dividend per Share Total Cash Dividend First quarter $ 0.25 $ 22.6 $ 0.25 $ 22.2 Second quarter $ 0.25 $ 22.6 $ 0.25 $ 22.3 Third quarter $ 0.25 $ 22.5 $ 0.25 $ 22.3 Fourth quarter $ 0.25 $ 22.5 $ 0.25 $ 22.3

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted-average assumptions used for calculating the fair value of its stock options and warrants with the Black-Scholes valuation model	The following table presents the weighted-average assumptions used in the Black-Scholes valuation model by the Company in calculating the fair value of its employee and officer stock options that have been granted: Years Ended December 31, 2017 2016 2015 Expected life (in years) 5.43 5.26 5.30 Expected stock price volatility 35.27 % 33.38 % 25.78 % Expected dividend yield 2.61 % 2.87 % 2.30 % Risk-free interest rate 2.14 % 1.16 % 1.58 % Fair value of options $ 10.63 $ 4.60 $ 8.81 The fair value of each stock option or warrant awarded to advisors and financial institutions is estimated on the date of grant and revalued at each reporting period using the Black-Scholes valuation model with the following weighted-average assumptions used: Years Ended December 31, 2017 2016 2015 Expected life (in years) 5.00 5.90 5.25 Expected stock price volatility 35.34 % 35.19 % 25.91 % Expected dividend yield 2.00 % 2.87 % 2.35 % Risk-free interest rate 2.14 % 2.13 % 1.84 % Fair value of options $ 24.93 $ 11.72 $ 12.12
Summary of the Company's activity in its stock option and warrant plans	The following table summarizes the Company’s stock option and warrant activity as of and for the year ended December 31, 2017 : Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (In thousands) Outstanding — December 31, 2016 7,153,982 $ 30.40 Granted 851,810 $ 39.48 Exercised (2,727,774 ) $ 30.17 Forfeited and Expired (411,519 ) $ 34.83 Outstanding — December 31, 2017 4,866,499 $ 31.73 5.87 $ 123,636 Exercisable — December 31, 2017 3,068,227 $ 32.29 4.32 $ 76,245 Exercisable and expected to vest — December 31, 2017 4,788,088 $ 31.69 5.82 $ 121,869
Summary of information about outstanding stock options and warrants	The following table summarizes information about outstanding stock options and warrants as of December 31, 2017 : Outstanding Exercisable Range of Exercise Prices Total Number of Shares Weighted- Average Remaining Life (Years) Weighted- Average Exercise Price Number of Shares Weighted- Average Exercise Price $18.04 - $23.02 1,642,309 5.96 $ 20.31 818,587 $ 20.78 $23.41 - $30.00 770,107 3.75 $ 28.16 734,811 $ 28.31 $31.60 - $32.33 408,375 4.66 $ 31.86 408,375 $ 31.86 $34.00 - $39.60 1,247,074 6.89 $ 37.56 481,722 $ 34.50 $42.59 - $54.81 798,634 6.76 $ 49.52 624,732 $ 50.64 4,866,499 5.87 $ 31.73 3,068,227 $ 32.29
Summary of the status of the Company's restricted stock	The following summarizes the Company’s activity in its restricted stock awards and stock units, which include restricted stock units, deferred stock units, and performance stock units, for the year ended December 31, 2017 : Restricted Stock Awards Stock Units Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Nonvested — December 31, 2016 10,404 $ 35.85 982,253 $ 30.61 Granted 18,700 $ 39.73 470,063 $ 40.10 Vested (16,308 ) $ 37.25 (385,999 ) $ 36.33 Forfeited — $ — (109,194 ) $ 31.92 Nonvested — December 31, 2017 12,796 $ 39.73 957,123 $ 32.81 Expected to vest — December 31, 2017 12,796 $ 39.73 902,829 $ 32.52

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Basic and diluted earnings per share	The calculation of basic and diluted earnings per share for the years noted was as follows (in thousands, except per share data): Years Ended December 31, 2017 2016 2015 Net income $ 238,863 $ 191,931 $ 168,784 Basic weighted-average number of shares outstanding 90,002 89,072 95,273 Dilutive common share equivalents 2,113 941 1,513 Diluted weighted-average number of shares outstanding 92,115 90,013 96,786 Basic earnings per share $ 2.65 $ 2.15 $ 1.77 Diluted earnings per share $ 2.59 $ 2.13 $ 1.74

Selected Quarterly Financial 44

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of selected quarterly financial data	2017 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net revenues $ 1,035,427 $ 1,065,504 $ 1,064,108 $ 1,116,442 Net income $ 48,189 $ 68,434 $ 58,142 $ 64,098 Basic earnings per share $ 0.54 $ 0.76 $ 0.65 $ 0.71 Diluted earnings per share $ 0.52 $ 0.74 $ 0.63 $ 0.69 Dividends declared per share $ 0.25 $ 0.25 $ 0.25 $ 0.25 2016 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Net revenues $ 1,005,305 $ 1,019,181 $ 1,017,440 $ 1,007,457 Net income $ 50,392 $ 47,849 $ 51,954 $ 41,736 Basic earnings per share $ 0.57 $ 0.54 $ 0.58 $ 0.47 Diluted earnings per share $ 0.56 $ 0.53 $ 0.58 $ 0.46 Dividends declared per share $ 0.25 $ 0.25 $ 0.25 $ 0.25

Organization and Description 45

Organization and Description of the Company (Details)	12 Months Ended
	Dec. 31, 2017
LPLH [Member]
Consolidation, Parent Ownership Interest [Line Items]
Ownership interest percentage in subsidiary	100.00%
LPL Financial [Member]
Consolidation, Parent Ownership Interest [Line Items]
Ownership interest percentage in subsidiary	100.00%
Number of states in which entity operates	50
Fortigent [Member]
Consolidation, Parent Ownership Interest [Line Items]
Ownership interest percentage in subsidiary	100.00%
IAG [Member]
Consolidation, Parent Ownership Interest [Line Items]
Ownership interest percentage in subsidiary	100.00%
LPLIA [Member]
Consolidation, Parent Ownership Interest [Line Items]
Ownership interest percentage in subsidiary	100.00%
PTCH [Member]
Consolidation, Parent Ownership Interest [Line Items]
Ownership interest percentage in subsidiary	100.00%

Summary of Significant Accoun46

Summary of Significant Accounting Policies Other Operating Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Interest expense from operations (did not exceed)	$ 1	$ 1

Summary of Significant Accoun47

Summary of Significant Accounting Policies Share-Based Compensation (Details) - Minimum [Member]	12 Months Ended
	Dec. 31, 2017
Stock options and warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	3 years
Restricted stock awards and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	1 year

Summary of Significant Accoun48

Summary of Significant Accounting Policies Receivables From and Payables to Clients (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Free credit balances held	$ 920,100	$ 836,600
Allowance for Doubtful Accounts Receivable [Roll Forward]
Provision for bad debts, net of recoveries	2,789	4,057	$ 2,542
Receivables from clients [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance - January 1	1,580	1,464
Provision for bad debts, net of recoveries	(15)	116
Ending balance - December 31	466	1,580	$ 1,464
Receivables from clients [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Write Off Of Allowances For Uncollectible Amounts	$ 1,099	$ 0

Summary of Significant Accoun49

Summary of Significant Accounting Policies Receivables from Advisor (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forgivable Loans Amortization Period, Minimum	3 years
Allowance for Doubtful Accounts Receivable [Roll Forward]
Provision for bad debts, net of recoveries	$ 2,789	$ 4,057	$ 2,542
Advisor Loans [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance - January 1	1,852	697
Provision for bad debts, net of recoveries	951	1,155
Write Off Of Allowances For Uncollectible Amounts	(2,914)	0
Provision for Bad Debt Reclassification Adjustment	3,375	0
Ending balance - December 31	$ 3,264	$ 1,852	$ 697

Summary of Significant Accoun50

Summary of Significant Accounting Policies Receivables From Others (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Forgivable Loans Amortization Period, Minimum	3 years
Forgivable Loans Amortization Period, Maximum	8 years
Forgivable Advisor Loans	$ 159,900,000
Allowance for Doubtful Accounts Receivable [Roll Forward]
Provision for bad debts, net of recoveries	2,789,000	$ 4,057,000	$ 2,542,000
Receivables from others [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance - January 1	12,851,000	9,856,000
Provision for bad debts, net of recoveries	1,853,000	2,786,000
Charge-offs, net of recoveries	(5,214,000)	209,000
Provision for Bad Debt Reclassification Adjustment	(3,375,000)	0
Ending balance - December 31	$ 6,115,000	$ 12,851,000	$ 9,856,000

Summary of Significant Accoun51

Summary of Significant Accounting Policies Securities Borrowed (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Securities borrowed, contract value	$ 12,489	$ 5,559
Securities borrowed, collateral market value	$ 12,100	$ 5,400

Summary of Significant Accoun52

Summary of Significant Accounting Policies Fixed Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Other Cost and Expense, Operating		$ 1	$ 1
Internally developed software [Member]
Property, Plant and Equipment [Line Items]
Fixed assets useful life (in years)	3 years
Computers and software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Fixed assets useful life (in years)	3 years
Computers and software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Fixed assets useful life (in years)	7 years
Furniture and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Fixed assets useful life (in years)	3 years
Furniture and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Fixed assets useful life (in years)	7 years

Summary of Significant Accoun53

Summary of Significant Accounting Policies Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment loss	$ 0	$ 0	$ 0
Impairment of Intangible Assets (Excluding Goodwill) [Abstract]
Impairment of intangible assets, indefinite-lived (excluding goodwill)	0	0	0
Impairment of intangible assets, finite-lived	$ 0	0	0
Forgivable Loans Amortization Period, Minimum	3 years
Finite-Lived Intangible Assets [Line Items]
Tangible Asset Impairment Charges	$ 0	$ 0	$ 0
Forgivable Loans Amortization Period, Maximum	8 years
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	5 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	20 years
Software Development [Member]
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Furniture and Fixtures [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Furniture and Fixtures [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	7 years

Summary of Significant Accoun54

Summary of Significant Accounting Policies Fair Value of Debt Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Borrowings	$ 2,396,250	$ 2,197,360
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$ 2,422,000	$ 2,218,900

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ in Thousands	Aug. 15, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		$ 98,400
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	$ 122,800
Goodwill acquired		61,931	$ 0
Payments to Acquire Businesses, Gross	$ 325,000	$ 162,500	$ 0	$ 0
Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Percentage, Low	72.00%
Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Percentage, High	93.50%

Fair Value Measurements Financi

Fair Value Measurements Financial Assets and Liabilities Measured on a Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	$ 17,879	$ 11,404
Securities sold, but not yet purchased	1,182	183
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	147,034	168,320
Securities owned — trading	17,879	11,404
Other assets	189,659	142,019
Total assets at fair value	354,572	321,743
Securities sold, but not yet purchased	1,182	183
Accounts payable and accrued liabilities		613
Total liabilities at fair value	1,182	796
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	147,034	168,320
Securities owned — trading	17,819	11,090
Other assets	180,377	134,914
Total assets at fair value	345,230	314,324
Securities sold, but not yet purchased	70	168
Accounts payable and accrued liabilities		0
Total liabilities at fair value	70	168
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Securities owned — trading	60	314
Other assets	9,282	7,105
Total assets at fair value	9,342	7,419
Securities sold, but not yet purchased	1,112	15
Accounts payable and accrued liabilities		86
Total liabilities at fair value	1,112	101
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Securities owned — trading	0	0
Other assets	0	0
Total assets at fair value	0	0
Securities sold, but not yet purchased	0	0
Accounts payable and accrued liabilities		527
Total liabilities at fair value	0	527
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	3
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	3
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	0
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	67	168
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	67	168
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	0	0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	0	0
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	1,112	15
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	0	0
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	1,112	15
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, but not yet purchased	0	0
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	288	474
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	288	474
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	10,850	7,585
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	10,850	7,585
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	201	35
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	201	35
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	60	314
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	60	314
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
U.S. Treasury Obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	6,480	2,996
U.S. Treasury Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	6,480	2,996
U.S. Treasury Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	0	0
U.S. Treasury Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned — trading	$ 0	$ 0

Held-to-Maturity Securities (De

Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of amortized cost, gross unrealized loss, and fair value of securities held-to-maturity
U.S. government notes - at amortized cost, Total	$ 11,833	$ 8,862
U.S. Treasury Securities [Member]
Summary of amortized cost, gross unrealized loss, and fair value of securities held-to-maturity
U.S. government notes - at amortized cost, Total	11,833	8,862
Gross unrealized loss	(86)	(31)
U.S. government notes - at fair value, Total	11,747	$ 8,831
U.S. Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of amortized cost, gross unrealized loss, and fair value of securities held-to-maturity
U.S. government notes - at fair value, Total	$ 11,747

Held-to-Maturity Securities (58

Held-to-Maturity Securities (Details 1) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Maturities of securities held-to-maturity
U.S. government notes - at amortized cost, Total	$ 11,833	$ 8,862
U.S. Treasury Securities [Member]
Maturities of securities held-to-maturity
U.S. government notes - at amortized cost, Within one year	5,006
U.S. government notes - at amortized cost, After one but within five years	6,327
U.S. government notes - at amortized cost, After five but within ten years	500
U.S. government notes - at amortized cost, Total	11,833	8,862
U.S. government notes - at fair value, Within one year	4,986
U.S. government notes - at fair value, After one but within five years	6,266
U.S. government notes - at fair value, After five but within ten years	495
U.S. government notes - at fair value, Total	11,747	$ 8,831
Fair Value, Inputs, Level 1 [Member] | U.S. Treasury Securities [Member]
Maturities of securities held-to-maturity
U.S. government notes - at fair value, Total	$ 11,747

Receivables from Product Spon59

Receivables from Product Sponsors, Broker-Dealers and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables:
Commissions receivable from product sponsors and others	$ 125,891	$ 116,218
Receivable from clearing organizations	62,561	50,656
Receivable from broker-dealers	1,389	1,309
Securities failed-to-deliver	6,366	6,939
Total receivables	196,207	175,122
Payables:
Payable to clearing organizations	13,316	26,517
Payable to broker-dealers	31,869	32,065
Securities failed-to-receive	9,077	4,450
Total payables	$ 54,262	$ 63,032

Fixed Assets (Details)

Fixed Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 84,071	$ 75,928	$ 73,383
Total fixed assets	840,028	743,287
Accumulated depreciation and amortization	(427,344)	(355,919)
Fixed assets, net	412,684	387,368
Internally developed software [Member]
Property, Plant and Equipment [Line Items]
Total fixed assets	346,029	293,997
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Total fixed assets	82,413	86,171
Computers and software [Member]
Property, Plant and Equipment [Line Items]
Total fixed assets	160,400	122,442
Building [Member]
Property, Plant and Equipment [Line Items]
Total fixed assets	105,939	105,939
Furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Total fixed assets	73,767	74,492
Land [Member]
Property, Plant and Equipment [Line Items]
Total fixed assets	4,678	4,678
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Total fixed assets	$ 66,802	$ 55,568

Fixed Assets (Details Textuals)

Fixed Assets (Details Textuals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 84,071	$ 75,928	$ 73,383
Finance and capital lease obligations	$ 3,906	$ 45,998	$ 59,940

Goodwill and Other Intangible62

Goodwill and Other Intangible Assets Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-lived Intangible Assets Acquired	$ 98,400
Goodwill [Roll Forward]
Goodwill, beginning balance	1,365,838	$ 1,365,838
Goodwill acquired	61,931	0
Goodwill, ending balance	$ 1,427,769	$ 1,365,838

Intangible Assets (Components)(

Intangible Assets (Components)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets [Line Items]
Total intangible assets	$ 414,093	$ 353,996
Definite-lived intangible assets:
Gross Carrying Value	793,340	694,952
Accumulated Amortization	(419,066)	(380,775)
Net Carrying Value	374,274	314,177
Trademarks and Trade Names [Member]
Indefinite-lived intangible assets:
Net Carrying Value	$ 39,819	$ 39,819
Advisor and financial institution relationships [Member]
Intangible Assets [Line Items]
Weighted-Average Life Remaining (in years)	8 years	9 years
Definite-lived intangible assets:
Gross Carrying Value	$ 538,921	$ 440,533
Accumulated Amortization	(269,294)	(244,540)
Net Carrying Value	$ 269,627	$ 195,993
Product sponsor relationships [Member]
Intangible Assets [Line Items]
Weighted-Average Life Remaining (in years)	8 years 1 month 6 days	9 years 1 month 6 days
Definite-lived intangible assets:
Gross Carrying Value	$ 234,086	$ 234,086
Accumulated Amortization	(137,615)	(125,620)
Net Carrying Value	$ 96,471	$ 108,466
Client relationships [Member]
Intangible Assets [Line Items]
Weighted-Average Life Remaining (in years)	6 years 9 months 18 days	7 years 8 months 12 days
Definite-lived intangible assets:
Gross Carrying Value	$ 19,133	$ 19,133
Accumulated Amortization	(11,477)	(10,055)
Net Carrying Value	$ 7,656	$ 9,078
Trade names [Member]
Intangible Assets [Line Items]
Weighted-Average Life Remaining (in years)	4 years 3 months 18 days	5 years 3 months 18 days
Definite-lived intangible assets:
Gross Carrying Value	$ 1,200	$ 1,200
Accumulated Amortization	(680)	(560)
Net Carrying Value	$ 520	$ 640

Goodwill and Other Intangible64

Goodwill and Other Intangible Assets (Details Textuals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill acquired	$ 61,931	$ 0
Intangible assets acquired during the period	98,400
Total amortization expense of intangible assets	$ 38,293	$ 38,035	$ 38,239

Intangible Assets (Future Amort

Intangible Assets (Future Amortization Expense)(Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Future amortization expense
2,018	$ 47,678
2,019	47,642
2,020	47,250
2,021	47,093
2,022	46,345
Thereafter	138,266
Net Carrying Value	$ 374,274	$ 314,177

Accounts Payable and Accrued 66

Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of accounts payable and accrued liabilities
Advisor deferred compensation plan liability	$ 177,652	$ 133,632
Accrued payroll	64,728	63,741
Deferred rent	41,629	43,817
Accounts payable	47,125	23,284
Other accrued liabilities	130,015	121,071
Total accounts payable and accrued liabilities	$ 461,149	$ 385,545

Debt (Credit Agreement Outstand

Debt (Credit Agreement Outstanding Balance)(Details) - USD ($) $ in Thousands	Sep. 21, 2017	Mar. 10, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2017
Long-term Debt, Current and Noncurrent [Abstract]
Balance				$ 2,385,022	$ 2,175,436
Total Borrowings				2,396,250	2,197,360
Debt Instrument, Unamortized Premium				11,584
Gain (Loss) on Extinguishment of Debt				(22,407)	0	$ 0
Deferred Finance Costs, Net				$ (22,812)
Repayments of Secured Debt	$ 200,000
Secured Debt [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Deferred Finance Costs, Net					$ (21,924)
Secured Debt [Member] | Fourth Amendment Agreement Term Loan B [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Interest Rate				3.81%
Total Borrowings	1,500,000			$ 1,496,250			$ 1,695,800
Debt Instrument, Amortization Payment, Percentage		0.25%
Debt Instrument, Call Premium, Percentage		1.00%
Secured Debt [Member] | Term Loan A [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Interest Rate					3.27%
Total Borrowings					$ 459,375
Secured Debt [Member] | Amended Term Loan B [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Interest Rate					4.80%
Total Borrowings					$ 693,000
Secured Debt [Member] | Extended Term Loan B [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Interest Rate					4.25%
Total Borrowings					$ 624,676
Secured Debt [Member] | New Term Loan B [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Interest Rate					3.25%
Total Borrowings					$ 420,309
Unsecured Debt [Member] | Additional Senior Unsecured Notes due 2025 [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Total Borrowings	400,000
Gain (Loss) on Extinguishment of Debt	$ 1,300
Debt Instrument, Redemption Price, Percentage	103.00%
Unsecured Debt [Member] | Senior Notes Due 2025 [Member]
Long-term Debt, Current and Noncurrent [Abstract]
Total Borrowings		$ 500,000		$ 900,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate				5.75%
Gain (Loss) on Extinguishment of Debt		$ 21,100
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed			100.00%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.25%
Long-term Debt, Current and Noncurrent [Abstract]
Interest Rate				0.00%
Total Borrowings				$ 0

Debt (Future Payments and Matur

Debt (Future Payments and Maturities)(Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2,016	$ 14,906
2,017	14,758
2,018	14,611
2,019	14,465
2,020	14,322
Thereafter	2,323,188
Total Borrowings	$ 2,396,250	$ 2,197,360

Debt (Credit Agreement Textuals

Debt (Credit Agreement Textuals)(Details) - USD ($)	Sep. 21, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2017	Mar. 10, 2017
Debt Instrument [Line Items]
Repayments of Secured Debt	$ 200,000,000
Number Of Uncommitted Lines Of Credit			3
Uncommitted lines of credit, unspecified limit			2
Line of Credit Facility, Average Outstanding Amount			$ 239,000,000	$ 105,000,000
Debt Instrument, Interest Rate During Period			2.61%	1.59%
Long-term Debt, Gross			$ 2,396,250,000	$ 2,197,360,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letters of credit, amount outstanding			$ 11,100,000
Applicable interest rate margin			1.25%
Line of credit, maximum borrowing capacity	500,000,000
Long-term Debt, Gross			$ 0
Line of Credit [Member]
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity			200,000,000
Additional Senior Unsecured Notes due 2025 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Gross	9,100,000
Long-term Debt, Gross	400,000,000
Senior Notes Due 2025 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 900,000,000			$ 500,000,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate			5.75%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		100.00%
Fourth Amendment Agreement Term Loan B [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 1,500,000,000		$ 1,496,250,000		$ 1,695,800,000

Income Taxes (Provision for Inc

Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current provision:
Federal	$ 117,745	$ 102,133	$ 123,633
State	17,353	15,002	20,291
Total current provision	135,098	117,135	143,924
Deferred benefit:
Federal	(8,951)	(10,767)	(24,972)
State	(440)	(783)	(5,181)
Total deferred benefit	(9,391)	(11,550)	(30,153)
Provision for income taxes	$ 125,707	$ 105,585	$ 113,771

Income Taxes (Reconciliation to

Income Taxes (Reconciliation to Effective Rate) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of company's effective income tax rate reconciliation
Federal statutory income tax rates	35.00%	35.00%	35.00%
State income taxes, net of federal benefit	3.00%	3.50%	3.60%
Non-deductible expenses	0.60%	0.30%	0.70%
Share-based compensation	(0.90%)	0.10%	0.00%
Business energy tax credit	(2.40%)	0.00%
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Percent	(0.90%)	(2.20%)	0.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent	(0.40%)	(1.10%)	0.00%
Other	0.50%	(0.10%)	1.00%
Effective income tax rates	34.50%	35.50%	40.30%

Income Taxes (Deferred Income T

Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued liabilities	$ 59,422	$ 75,907
Share-based compensation	17,122	31,715
State taxes	5,630	9,345
Deferred rent	32,457	49,544
Provision for bad debts	2,956	7,520
Net operating losses	0	(10)
Deferred Tax Assets, Tax Deferred Expense, Forgivable Loans	7,643	9,381
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Self Insurance	1,355	1,689
Other	0	956
Total deferred tax assets	126,585	186,047
Deferred tax liabilities:
Amortization of intangible assets	(75,043)	(122,482)
Depreciation of fixed assets	(63,213)	(88,960)
Other	(4,333)	(219)
Total deferred tax liabilities	(142,589)	(211,661)
Deferred income taxes, net	$ (16,004)	$ (25,614)

Income Taxes (Gross Unrecognize

Income Taxes (Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of gross unrecognized tax benefits including interest and penalties reconciliation
Balance - Beginning of year	$ 39,766	$ 24,747	$ 20,987
Increases for tax positions related to the current year	7,815	17,787	4,404
Reductions as a result of a lapse of the applicable statute of limitations	(4,924)	(2,768)	(644)
Balance - End of year	$ 42,657	$ 39,766	$ 24,747

Income Taxes (Details Textuals)

Income Taxes (Details Textuals) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, net of the federal benefit on state issues, favorable income tax rate effect	$ 37.6	$ 31.4
Unrecognized tax benefits, interest accrued	4.5	3.9
Unrecognized tax benefits, penalties accrued	4.4	$ 4.5
Reduction in unrecognized tax benefits related to the statute of limitations	$ 2.7

Commitments and Contingencies75

Commitments and Contingencies (Leases) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases, Operating [Abstract]
Rent expense for operating leases	$ 20.1	$ 24.7	$ 25.6
Future minimum sublease rental income	$ 14.2

Commitments and Contingencies76

Commitments and Contingencies (Future Minimum Payments) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,018	$ 63,430
2,019	46,463
2,020	35,057
2,021	32,416
2,022	32,741
Thereafter	270,252
Total	$ 480,359	[1]
[1]	Future minimum payments have not been reduced by minimum sublease rental income of $14.2 million

Commitments and Contingencies77

Commitments and Contingencies (Other Commitments) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Brokers and Dealers [Abstract]
Collateral Securities Repledged, Delivered, or Used	$ 270,900
Collateral security	379,200
Amount pledged with client-owned securities	49,900
Remaining collateral securities that can be sold, re-pledged or loaned	329,300
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Trading securities pledged to clearing organizations	6,500	$ 3,000
Leasehold Financing Obligation	$ 107,518	$ 105,649

Stockholders' Equity (Dividends

Stockholders' Equity (Dividends Paid) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Dividend paid per share of common stock	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25
Dividends		$ 22,500	$ 22,600	$ 22,600		$ 22,300	$ 22,300	$ 22,200
Total cash dividends paid during the quarter	$ 22,500				$ 22,300				$ 90,273	$ 89,081	$ 95,814

Stockholders' Equity (Share Rep

Stockholders' Equity (Share Repurchases) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 500,000				$ 500,000
Treasury stock purchases, shares	603,000	539,385	910,349	566,798	2,619,532
Treasury Stock Acquired, Average Cost Per Share	$ 49.76	$ 46.37	$ 39.78	$ 39.68	$ 43.42
Treasury Stock, Value, Acquired, Cost Method	$ 30,000	$ 25,000	$ 36,200	$ 22,500	$ 113,728	$ 25,013	$ 390,835
Commission Fee Paid Per Repurchased Share					$ 0.02

Share-Based Compensation Stock

Share-Based Compensation Stock Option and Warrant Assumptions (Details) - Stock options and warrants [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employees, officers, and directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected life (in years)	5 years 5 months 4 days	5 years 3 months 3 days	5 years 3 months 18 days
Expected stock price volatility	35.27%	33.38%	25.78%
Expected dividend yield	2.61%	2.87%	2.30%
Risk-free interest rate	2.14%	1.16%	1.58%
Fair value of options	$ 10.63	$ 4.60	$ 8.81
Advisors and Financial Institutions [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected life (in years)	5 years	5 years 10 months 24 days	5 years 3 months
Expected stock price volatility	35.34%	35.19%	25.91%
Expected dividend yield	2.00%	2.87%	2.35%
Risk-free interest rate	2.14%	2.13%	1.84%
Fair value of options	$ 24.93	$ 11.72	$ 12.12

Share-Based Compensation Stoc81

Share-Based Compensation Stock Option and Warrant Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares Outstanding, Beginning Balance | shares	7,153,982
Number of Shares, Granted | shares	851,810
Number of Shares, Exercised | shares	(2,727,774)
Number of Shares, Forfeited | shares	(411,519)
Number of Shares Outstanding, Ending Balance | shares	4,866,499
Number of Shares, Exercisable, Ending Balance | shares	3,068,227
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted-Average Exercise Price, Outstanding, Beginning Balance | $ / shares	$ 30.40
Weighted-Average Exercise Price, Granted | $ / shares	39.48
Weighted-Average Exercise Price, Exercised | $ / shares	30.17
Weighted-Average Exercise Price, Forfeited and Expired | $ / shares	34.83
Weighted-Average Exercise Price, Outstanding, Ending Balance | $ / shares	31.73
Weighted-Average Exercise Price, Exercisable, Ending Balance | $ / shares	32.29
Weighted-Average Exercise Price, Exercisable and expected to vest (in dollars per share) | $ / shares	$ 31.69
Weighted-Average Remaining Contractual Term for Options Outstanding	5 years 10 months 13 days
Weighted-Average Remaining Contractual Term for Options Exercisable	4 years 3 months 25 days
Aggregate Intrinsic Value, Outstanding, Ending Balance | $	$ 123,636
Aggregate Intrinsic Value, Exercisable, Ending Balance | $	$ 76,245
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number | shares	4,788,088
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	5 years 9 months 25 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value | $	$ 121,869

Share-Based Compensation Outsta

Share-Based Compensation Outstanding Stock Options and Warrants (Details)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Summary of information about outstanding stock options and warrants
Total Number of Shares, Outstanding | shares	4,866,499
Weighted-Average Remaining Life, Outstanding	5 years 10 months 13 days
Weighted-Average Exercise Price, Outstanding | $ / shares	$ 31.73
Number of Shares, Exercisable | shares	3,068,227
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 32.29
$18.04 - $23.02
Summary of information about outstanding stock options and warrants
Total Number of Shares, Outstanding | shares	1,642,309
Weighted-Average Remaining Life, Outstanding	5 years 11 months 15 days
Weighted-Average Exercise Price, Outstanding | $ / shares	$ 20.31
Number of Shares, Exercisable | shares	818,587
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 20.78
$23.41 - $30.00
Summary of information about outstanding stock options and warrants
Total Number of Shares, Outstanding | shares	770,107
Weighted-Average Remaining Life, Outstanding	3 years 9 months
Weighted-Average Exercise Price, Outstanding | $ / shares	$ 28.16
Number of Shares, Exercisable | shares	734,811
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 28.31
$31.60 - $32.33
Summary of information about outstanding stock options and warrants
Total Number of Shares, Outstanding | shares	408,375
Weighted-Average Remaining Life, Outstanding	4 years 7 months 28 days
Weighted-Average Exercise Price, Outstanding | $ / shares	$ 31.86
Number of Shares, Exercisable | shares	408,375
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 31.86
$34.00 - $39.60
Summary of information about outstanding stock options and warrants
Total Number of Shares, Outstanding | shares	1,247,074
Weighted-Average Remaining Life, Outstanding	6 years 10 months 20 days
Weighted-Average Exercise Price, Outstanding | $ / shares	$ 37.56
Number of Shares, Exercisable | shares	481,722
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 34.50
$42.59 - $54.81
Summary of information about outstanding stock options and warrants
Total Number of Shares, Outstanding | shares	798,634
Weighted-Average Remaining Life, Outstanding	6 years 9 months 3 days
Weighted-Average Exercise Price, Outstanding | $ / shares	$ 49.52
Number of Shares, Exercisable | shares	624,732
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 50.64

Share-Based Compensation Restri

Share-Based Compensation Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 39.73
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares, Beginning Balance	10,404
Number of Shares, Granted	18,700
Number of Shares, Vested	(16,308)
Number of Shares, Forfeited	0
Number of Shares, Ending Balance	12,796	10,404
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	12,796
Weighted-Average Grant-Date Fair Value, Beginning Balance	$ 35.85
Weighted-Average Grant-Date Fair Value, Granted	39.73
Weighted-Average Grant-Date Fair Value, Forfeited	0
Weighted-Average Grant-Date Fair Value, Ending Balance	39.73	$ 35.85
Weighted-Average Grant-Date Fair Value, Vested	$ 37.25
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares, Beginning Balance	982,253
Number of Shares, Granted	470,063
Number of Shares, Vested	(385,999)
Number of Shares, Forfeited	(109,194)
Number of Shares, Ending Balance	957,123	982,253
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	902,829
Weighted-Average Grant-Date Fair Value, Beginning Balance	$ 30.61
Weighted-Average Grant-Date Fair Value, Granted	40.10
Weighted-Average Grant-Date Fair Value, Forfeited	31.92
Weighted-Average Grant-Date Fair Value, Ending Balance	32.81	$ 30.61
Weighted-Average Grant-Date Fair Value, Vested	36.33
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 32.52
Advisors and Financial Institutions [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 7.3	$ 2.7	$ 2.5

Share-Based Compensation (Detai

Share-Based Compensation (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Authorized shares	20,055,945
Authorized unissued shares	7,287,382
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	7,813,333
Employees, officers, and directors [Member] | Stock options and warrants [Member]
Share-based Compensation [Abstract]
Share based compensation expense	$ 7.2	$ 10.7	$ 14.5
Share based compensation cost unrecognized	$ 7.8
Non-vested compensation cost weighted-average period	1 year 9 months 29 days
Employees, officers, and directors [Member] | Restricted Stock [Member]
Share-based Compensation [Abstract]
Share based compensation expense	$ 11.5	8.9	8.3
Share based compensation cost unrecognized	$ 13
Non-vested compensation cost weighted-average period	1 year 11 months 8 days
Advisors and Financial Institutions [Member] | Stock options and warrants [Member]
Share-based Compensation [Abstract]
Share based compensation expense	$ 1.8	1.8	3.4
Advisors and Financial Institutions [Member] | Restricted Stock Units [Member]
Share-based Compensation [Abstract]
Share based compensation expense	7.3	$ 2.7	$ 2.5
Share based compensation cost unrecognized	$ 6.4
Non-vested compensation cost weighted-average period	1 year 8 months 4 days
Minimum [Member] | Stock options and warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Minimum [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income	$ 64,098	$ 58,142	$ 68,434	$ 48,189	$ 41,736	$ 51,954	$ 47,849	$ 50,392	$ 238,863	$ 191,931	$ 168,784
Basic weighted average number of shares outstanding									90,002	89,072	95,273
Dilutive common share equivalents									2,113	941	1,513
Diluted weighted average number of shares outstanding									92,115	90,013	96,786
Basic earnings per share	$ 0.71	$ 0.65	$ 0.76	$ 0.54	$ 0.47	$ 0.58	$ 0.54	$ 0.57	$ 2.65	$ 2.15	$ 1.77
Diluted earnings per share	$ 0.69	$ 0.63	$ 0.74	$ 0.52	$ 0.46	$ 0.58	$ 0.53	$ 0.56	$ 2.59	$ 2.13	$ 1.74

Earnings per Share (Details Tex

Earnings per Share (Details Textuals) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of Earnings per Share amount	1,909,288	4,054,972	2,223,886

Employee and Advisor Benefit 87

Employee and Advisor Benefit Plans (Details Textuals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee and Advisor Benefit Plans [Abstract]
Percentage of eligible compensation matched by employer	65.00%
Percentage of employee compensation eligible for match	8.00%
Total contribution cost recognized	$ 10,500	$ 10,100	$ 9,900
Employee stock purchase plan purchase price discount	15.00%
Deferred Compensation Arrangement with Individual, Recorded Liability	$ 177,652	$ 133,632
Deferred Compensation Arrangements [Abstract]
Deferred Compensation Arrangement with Individual, Contributions by Employer	176,900
Deferred Compensation Arrangement with Individual, Compensation Expense	3,500
Deferred Compensation Arrangement, Rabbi Trust, Recorded Liability	$ 1,800

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) shares in Thousands, $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Treasury stock purchases, shares	603,000	539,385	910,349	566,798	2,619,532
TPG Capital [Member]
Related Party Transaction [Line Items]
Related party revenues					$ 3.1	$ 0.1	$ 0.6
Related party expenses					$ 1.9	$ 1.5	$ 6.8

Net Capital and Regulatory Re89

Net Capital and Regulatory Requirements (Details) $ in Millions	Dec. 31, 2017USD ($)
Brokers and Dealers [Abstract]
Net Capital	$ 99.5
Minimum Net Capital Required for Broker-Dealer Subsidiary	$ 7.8

Selected Quarterly Financial 90

Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 1,116,442	$ 1,064,108	$ 1,065,504	$ 1,035,427	$ 1,007,457	$ 1,017,440	$ 1,019,181	$ 1,005,305	$ 4,281,481	$ 4,049,383	$ 4,275,054
Net income	$ 64,098	$ 58,142	$ 68,434	$ 48,189	$ 41,736	$ 51,954	$ 47,849	$ 50,392	$ 238,863	$ 191,931	$ 168,784
Basic earnings per share	$ 0.71	$ 0.65	$ 0.76	$ 0.54	$ 0.47	$ 0.58	$ 0.54	$ 0.57	$ 2.65	$ 2.15	$ 1.77
Diluted earnings per share	0.69	0.63	0.74	0.52	0.46	0.58	0.53	0.56	$ 2.59	$ 2.13	$ 1.74
Dividends declared per share	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25

Subsequent Event (Details)

Subsequent Event (Details) - $ / shares	Mar. 23, 2018	Mar. 09, 2018	Feb. 16, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017
Subsequent Event [Line Items]
Treasury Stock Acquired, Average Cost Per Share				$ 49.76	$ 46.37	$ 39.78	$ 39.68	$ 43.42
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends Payable, Date Declared			Feb. 16, 2018
Dividends Payable, Amount Per Share			$ 0.25
Dividends Payable, Date to be Paid	Mar. 23, 2018
Dividends Payable, Date of Record		Mar. 9, 2018