Medifast (MED) 10-Q 4 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 27, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Entity Registrant Name	MEDIFAST INC
Entity Central Index Key	910,329
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding		12,062,532

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenue	$ 98,596	$ 70,622
Cost of sales	23,788	17,730
Gross profit	74,808	52,892
Selling, general, and administrative	60,125	44,283
Income from operations	14,683	8,609
Other income (expense)
Interest and dividend income, net	249	63
Other income (expense)	(1)	39
Nonoperating income (expense)	248	102
Income from continuing operations before income taxes	14,931	8,711
Provision for income taxes on continuing operations	2,709	2,566
Net income	$ 12,222	$ 6,145
Basic earnings per share
Earnings Per Share, Basic	$ 1.02	$ 0.52
Diluted earnings per share
Earnings Per Share, Diluted	$ 1.01	$ 0.51
Weighted average shares outstanding -
Basic	12,030	11,901
Diluted	12,139	12,009
Cash dividends declared per share	$ 0.48	$ 0.32

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Other Comprehensive Income [Abstract]
Net income	$ 12,222	$ 6,145
Other comprehensive income (loss), net of tax
Foreign currency translation		2
Change in fair value of marketable securities	(84)	124
Adjustment for net losses (gains) realized and included in net income		10
Total change in unrealized gains (losses) on marketable securities	(84)	134
Other comprehensive income (loss)	(84)	136
Comprehensive income	$ 12,138	$ 6,281

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 86,963	$ 75,077
Accounts receivable-net of allowance for doubtful accounts of $98 at March 31, 2018 and allowance for sales returns and doubtful accounts of $597 at December 31, 2017	1,025	576
Inventory	17,288	19,328
Investment securities	22,278	23,757
Income taxes, prepaid		2,272
Prepaid expenses and other current assets	3,577	4,188
Deferred tax assets	426
Total current assets	131,131	125,198
Property, plant and equipment - net	18,358	18,611
Other assets	1,902	2,120
Deferred tax assets	426
TOTAL ASSETS	151,817	145,929
Current liabilities:
Accounts payable and accrued expenses	38,187	37,140
Total current liabilities	38,187	37,140
Other liabilities:
Deferred tax liabilities		208
Total liabilities	38,187	37,348
Stockholders' Equity:
Common stock; par value $.001 per share; 20,000 shares authorized; 12,139 and 12,103 issued and 12,063 and 11,971 outstanding at March 31, 2018 and December 31, 2017, respectively	12	12
Additional paid-in capital	6,369	4,967
Accumulated other comprehensive loss	(244)	(160)
Retained earnings	108,243	103,762
Less: Treasury stock at cost, 9 shares at March 31, 2018	(750)
Total stockholders' equity	113,630	108,581
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 151,817	$ 145,929

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 98
Accounts receivable, allowance for sales returns and doubtful accounts		$ 597
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	20,000,000	20,000,000
Common stock, issued	12,139,000	12,103,000
Common stock, outstanding	12,063,000	11,971,000
Treasury Stock, Common, Shares	9,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 12,222	$ 6,145
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	1,544	1,076
Share-based compensation	805	957
Loss (gain) on sale of disposal of property, plant and equipment	214	(49)
Realized loss (gain) on investment securities, net	57	60
Amortization of premium on investment securities	153	194
Deferred income taxes	(105)	(242)
Changes in operating assets and liabilities:
Accounts receivable	108	(102)
Inventory	2,942	(1,572)
Income taxes, prepaid	2,738	865
Prepaid expenses and other current assets	727	577
Other assets	(1)	(4)
Accounts payable and accrued expenses	(3,396)	(1,222)
Net cash flow provided by operating activities	18,008	6,683
Investing Activities:
Sale of investment securities	1,200	760
Purchase of investment securities		(1,365)
Sale of property and equipment		59
Purchase of property and equipment	(1,286)	(470)
Net cash flow used in investing activities	(86)	(1,016)
Financing Activities:
Options exercised by executives and directors	62	568
Net shares repurchased for employee taxes	(215)	(825)
Cash dividends paid to stockholders	(5,883)	(3,878)
Net cash used in financing activities	(6,036)	(4,135)
Foreign currency impact		2
Increase in cash and cash equivalents	11,886	1,534
Cash and cash equivalents - beginning of the period	75,077	52,436
Cash and cash equivalents - end of period	86,963	53,970
Supplemental disclosure of cash flow information:
Income taxes paid		1,928
Dividends declared included in accounts payable	$ 5,943	$ 3,991

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - 3 months ended Mar. 31, 2018 - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid- In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance (Scenario, Previously Reported [Member]) at Dec. 31, 2017	$ 12	$ 4,967	$ (160)	$ 101,744		$ 106,563
Balance (Restatement Adjustment [Member])				(2,018)		(2,018)
Balance at Dec. 31, 2017	$ 12	4,967	(160)	103,762		108,581
Balance (in shares) (Scenario, Previously Reported [Member]) at Dec. 31, 2017	12,103
Balance (in shares) at Dec. 31, 2017	12,103
Net income				12,222		12,222
Share-based compensation		805				805
Share-based compensation (in shares)	16
Options exercised by executives and directors		62				62
Options exercised by executives and directors (in shares)	14
Net shares repurchased for employee taxes		(215)				(215)
Net shares repurchased for eimployee taxes, (in shares)	(3)
Treasury stock from cashless options	$ 9	750			$ (750)
Other comprehensive income (loss)			(84)			(84)
Cash dividends declared to stockholders				(5,723)		(5,723)
Balance at Mar. 31, 2018	$ 12	$ 6,369	$ (244)	$ 108,243	$ (750)	$ 113,630
Balance (in shares) at Mar. 31, 2018	12,139

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation - The accompanying unaudited condensed consolidated financial statements of Medifast, Inc. and its wholly-owned subsidiaries (the “Company,” “we,” “us,” or “our”) included herein have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”), for interim information and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for reporting on Form 10-Q. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. However, in the opinion of management, all adjustments consisting of normal, recurring adjustments considered necessary for a fair presentation of the financial position and results of operations have been included and management believes the disclosures that are made are adequate to make the information presented not misleading. The condensed consolidated balance sheet at December 31, 2017 has been derived from the audited consolidated financial statements at that date. The results of operations for the three months ended March 31, 2018 are not necessarily indicative of results that may be expected for the fiscal year ending December 31, 2018. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the 2017 audited consolidated financial statements and notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 (“2017 Form 10-K”).  Presentation of Financial Statements - The unaudited condensed consolidated financial statements included herein include the accounts of the Medifast, Inc. and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated. Use of Estimates - The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. Actual results could differ materially from those estimates. Accounting Pronouncements Adopted in 2018 – In May 2014, the FASB issued ASU 2014-09 , Revenue from Contracts with Customers (Topic 606) . The new revenue recognition standard requires the Company to recognize revenue for the transfer of goods or services to customers for the amount the Company expects to be entitled to receive in exchange for those goods or services. The Company is required to identify the contract, identify the relevant performance obligations, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize the revenue when the entity satisfies a performance obligation. Companies have the option of using either a full retrospective or a modified retrospective approach to adopt the guidance. On January 1, 2018, the Company adopted the new revenue standard on a modified retrospective basis and recorded an after-tax transition adjustment to reduce retained earnings as of January 1, 2018 by $2.0 million. This is comprised of $5.6 million of revenue offset by $3.6 million of inventory costs, deferred shipping expense, credit card fees and income taxes. The results of ASU 606 primarily impact the Company’s timing of revenue recognition for product shipments, as product revenue is recognized upon customer receipt in lieu of at the time of shipment. The new standard requires more extensive revenue-related disclosures. As required by ASC 606, the impact of the adoption of the new revenue standard on our Condensed Consolidated Statements of Income and Condensed Consolidated Balance Sheets was as follows (in thousands):    Three months ended March 31, 2018  As Reported Balances without adoption of ASC 606 Effect of Change   Revenue $ 98,596 $ 97,254 $ 1,342  Cost of sales 23,788 23,521 (267)  Gross profit 74,808 73,733 1,075   Selling, general, and administrative 60,125 59,523 (602)   Income from operations 14,683 14,210 473   Other income (expense)  Interest income, net 249 249 -  Other income (expense) (1) (1) -  248 248 -   Income from operations before income taxes 14,931 14,458 473   Provision for income taxes 2,709 2,608 (101)   Net income $ 12,222 $ 11,850 $ 372   Earnings per share - basic $ 1.02 $ 0.99 $ 0.03   Earnings per share - diluted $ 1.01 $ 0.98 $ 0.03   Weighted average shares outstanding -  Basic 12,030 12,030  Diluted 12,139 12,139     March 31, 2018  As Reported Balances without adoption of ASC 606 Effect of Change   ASSETS  Accounts receivable, net $ 1,025 $ 92 $ 933  Inventory 17,288 16,624 664  Prepaid expenses and other current assets 3,577 3,491 86  Deferred tax assets 426 - 426   LIABILITIES  Accounts payable and accrued expenses 38,187 34,416 3,771  Deferred tax liabilities - 16 (16)   Stockholders' Equity  Retained earnings 108,243 109,889 (1,646)  The cumulative effect of the changes made to our January 1, 2018 Condensed Consolidated Balance Sheet from the modified retrospective adoption of ASC 606 was as follows (in thousands):    Balance at December 31, 2017 Adjustments due to ASC 606 Balance at January 1, 2018   ASSETS  Accounts receivable, net $ 576 $ 557 $ 1,133  Inventory 19,328 902 20,230  Prepaid expenses and other current assets 4,188 116 4,304  Deferred tax assets - 336 336   LIABILITIES  Accounts payable and accrued expenses 37,140 4,137 41,277  Deferred tax liabilities 208 (208) -   Stockholders' Equity  Retained earnings 103,762 (2,018) 101,744   Recent Accounting Pronouncements – We have considered all new accounting pronouncements and have concluded that there are no new pronouncements that may have a material impact on our results of operations, financial condition, or cash flows, based on current information, except for: ASU 2016-02, Leases (Topic 842) requires the rights and obligations of all leased assets with a term greater than 12 months to be presented on the balance sheet. The pronouncement is effective for fiscal years beginning after December 15, 2018. The Company currently expects that upon adoption of ASU 2016-02 right-to-use assets and lease liabilities will be recognized in the Company’s Consolidated Balance Sheet in amounts that will be material. Management is currently evaluating the effect that the provisions of ASU 2016-02 will have on the Company’s financial statements. ASU 2018-02, Income Statement Reporting - Comprehensive Income (Topic 220) allows the reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from tax effects resulting from the Tax Cuts and Jobs Act and will improve the usefulness of information reported to financial statement users. However, because the amendments only relate to the reclassification of the income tax effects of the Tax Cuts and Jobs Act, the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. The amendments in this Update are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Management is currently evaluating the effect that the provisions of ASU 2018-02 will have on the Company’s financial statements. 

Revenue

Revenue	3 Months Ended
	Mar. 31, 2018
Revenue [Abstract]
Revenue	2. REVENUE Revenue recognition Our revenue is derived primarily from point of sale transactions executed over an e-commerce platform for weight loss, weight management, and other consumable health and nutritional products and recognized upon receipt by customer and net of discounts, rebates, promotional adjustments, price adjustments, allocated consideration to loyalty programs and estimated returns. Revenue is recognized when control of the promised products are transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for transferring those products . When determining whether the customer has obtained control the products, we consider any future performance obligations. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account in ASC 606. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. O ur contracts have performance obligation s to fulfill and deliver products from the point of sale transaction along with the related customer reward programs . Our performance obligations are satisfied at a point in time. Revenue from products transferred to customers at a point in time accounted for substantially all of our revenue for the three-month periods ended March 31, 2018 and 2017, respectively. Revenue on these contracts is recognized when obligations under the terms of the contract with our customer are satisfied . G enerally , this occurs with the transfer of control upon receipt of products by our customers. Any consideration received prior to the fulfillment of the Company performance obligation is deferred and recognized as a liability. Sales returns Our return policy allows for customer returns within 30 days of purchase and upon our authorization. W e adjust revenues for the products expected to be returned and a liability is recognized for expected refunds to customers. We estimate expected returns based on historical levels and project this experience into the future. Customer reward programs and sales incentives Our sales contracts may give customers the option to purchase additional products priced at a discount. Options to acquire additional products at a discount can come in many forms, such as customer reward programs and incentive offerings including pricing arrangements, and promotions. We reduce the transaction price for certain customer reward programs and incentive offerings including pricing arrangements, promotions , incentives that represent variable consideration and separate performance obligations . The Company accounts for sales rewards as a separate performance obligation of the transactions , and therefore allocates consideration between the initial sale of products and the customer reward program and incentive offering . Shipping and handling costs Amounts billed to customers for shipping and handling activities are treated as a promised service performance obligation and recorded in revenue in the accompanying Condensed Consolidated Statements of Income upon fulfillment of the performance obligation . Shipping and handling costs incurred by the Company for the delivery of products to customers are considered a cost to fulfill the contract and are included in c ost of sales in the accompanying Condensed Consolidated Statements of Income. Contract costs W e expense sales commissions and credit card fees during the period in which the corresponding revenue is earned . These costs are deferred along with the revenues for goods that are in transit and not received by customers by period end. These costs are recorded in selling, general and administrative expense in the Condensed Consolidated Statements of Income. Disaggregated revenue and entity-wide revenue disclosures The nature, amount, timing, and uncertainty of revenue and cash flows from our revenues amongst contracts, product offerings and customers do not differentiate and are recognized consistently based on policies discussed above. In addition, e ffective January 1 , 2018, we changed how we internally and externally report our revenues to simplify and align with changes in how we manage our business, review operating performance and allocate resources as a result of our primary focus on the OPTA VIA business and the significance this business represents to the overall results of the Company. We considered the following factors in determ in ing this decision: the nature of business activities overlapping amongst previous defined sales channels, the management structure directly accountable to our chief operating decision maker for operating and administrative activities, and information presented to the Board of Directors and investors. We previously disclosed entity-wide disclosures for sales by channel : OPTA VIA, Medifast Direct, Franchise Medifast Weight Control Centers and Medifast Wholesale. Due to the interchangeable nature of these customers amongst sale channels, sales migration to OPTA VIA, and realignment of internal operations as discussed, future disclosure will not include revenues by sales channel.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2018
Inventories [Abstract]
Inventories	3. INVENTORIES Inventories consist principally of packaged meal replacements held in the Company’s warehouses. Inventory is stated at the lower of cost or net realizable value, utilizing the first-in, first-out method. The cost of finished goods includes the cost of raw materials, packaging supplies, direct and indirect labor and other indirect manufacturing costs. On a quarterly basis, management reviews inventory for unsalable or obsolete inventory. Inventories consisted of the following (in thousands):      March 31, 2018 December 31, 2017   Raw materials $ 4,283 $ 4,348  Packaging 1,247 1,185  Non-food finished goods 1,034 920  Finished goods 10,958 13,407  Reserve for obsolete inventory (234) (532)  Total $ 17,288 $ 19,328  

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	4. EARNING PER SHARE Basic earnings per share (“EPS”) computations are calculated utilizing the weighted average number of shares of common stock outstanding during the periods presented. Diluted EPS is calculated utilizing the weighted average number of shares of common stock outstanding adjusted for the effect of dilutive common stock equivalents. The following table sets forth the computation of basic and diluted EPS (in thousands, except per share data):    Three months ended March 31,  2018 2017   Numerator:  Net income $ 12,222 $ 6,145   Denominator:  Weighted average shares of common stock outstanding 12,030 11,901  Effect of dilutive common stock equivalents 109 108  Weighted average shares of common stock outstanding 12,139 12,009   Earnings per share - basic $ 1.02 $ 0.52   E arnings per share - diluted $ 1.01 $ 0.51  The calculation of diluted earnings per share excluded 4,690 and 4,531 antidilutive options outstanding for the three months ended March 31, 2018 and 2017, respectively.

Shared-based Compensation

Shared-based Compensation	3 Months Ended
	Mar. 31, 2018
Share-based Compensation [Abstract]
Shared-based Compensation	5. SHARE-BASED COMPENSATION Stock Options:  The Company has issued non-qualified and incentive stock options to employees and nonemployee directors. The fair value of these options are estimated on the date of grant using the Black-Scholes option pricing model, which requires estimates of the expected term of the option, the risk-free interest rate, the expected volatility of the price of the Company’s common stock, and dividend yield. Options outstanding as of March 31, 2018 generally vest over a period of three years and expire ten years from the date of grant. The exercise price of these options ranges from $26.52 to $66.68 . Due to the Company’s lack of option exercise history, the expected term is calculated using the simplified method defined as the midpoint between the vesting period and the contractual term of each option. The risk free interest rate is based on the U.S. Treasury yield curve in effect on the date of grant that most closely corresponds to the expected term of the option. The expected volatility is based on the historical volatility of the Company’s common stock over the period of time equivalent to the expected term for each award. The weighted average input assumptions used were as follows:     2018 2017   Expected term (in years) 6.4 6.0  Risk-free interest rate 2.64% 2.05%  Expected volatility 33.31% 38.33%  Dividend yield 2.88% 2.40%   The following table is a summary of our stock option activity:     Three months ended March 31,  2018 2017  Shares Weighted-Average Exercise Price Shares Weighted-Average Exercise Price  (shares in thousands)  Outstanding at beginning of period 106 $ 31.18 129 $ 28.22  Granted 51 66.68 38 44.73  Exercised (21) 28.87 (21) 27.38  Forfeited - - (9) 38.18  Outstanding at end of the period 136 $ 44.79 137 $ 32.20  Exercisable at end of the period 60 $ 29.94 63 $ 28.15  As of March 31, 2018, the weighted-average remaining contractual life was 8.44 years with an aggregate intrinsic value of $6.6 million for outstanding stock options and the weighted-average remaining contractual life was 7.27 years with an aggregate intrinsic value of $3.8 million for exercisable options. The weighted-average grant date fair value of options granted during the three months ended March 31, 2018 and 2017 was $ 17.79 and $13.73 , respectively. The unrecognized compensation expense calculated under the fair value method for shares expected to vest as of March 31, 2018 was $1.1 million and is expected to be recognized over a weighted average period of 3.73 years. The Company received $62 thousand and $568 thousand in cash proceeds from the exercise of stock options during the three months ended March 31, 2018 and 2017, respectively. The total intrinsic value for options exercised during the three months ended March 31, 2018 and 2017 was $1.4 million and $325 thousand, respectively.  Restricted Stock: The Company has issued restricted stock to employees and nonemployee directors generally with vesting terms up to five years after the date of grant. The fair value is equal to the market price of the Company’s common stock on the date of grant. Expense for restricted stock is amortized ratably over the vesting period. The following table summarizes our restricted stock activity:     Three months ended March 31,  2018 2017  Shares Weighted-Average Grant Date Fair Value Shares Weighted-Average Grant Date Fair Value  (shares in thousands)  Outstanding at beginning of period 129 $ 32.15 215 $ 27.69  Granted 16 66.68 44 44.73  Vested (69) 28.35 (55) 25.94  Forfeited - - (6) 32.80  Outstanding at end of the period 76 $ 42.99 198 $ 31.79 The total fair value of restricted stock awards vested during the three months ended March 31, 2018 and 2017 was $4.8 million and $2.4 million, respectively. The total share-based compensation charged against income during the three months ended March 31, 2018 and 2017 was $805 thousand and $957 thousand, respectively. The total costs of the options and restricted stock awards charged against income during the three months ended March 31, 2018 and 2017 was $580 thousand and $733 thousand, respectively. Also included for the three months ended March 31, 2018 and 2017 was $73 thousand for 63,300 shares and $72 thousand for 147,675 shares, respectively, in expense that will vest based on certain market and performance conditions for certain key executives. Included for the three months ended March 31, 2018 and 2017 was $152 thousand in expense for 210,000 deferred shares that will vest based on certain performance conditions for our CEO. The total income tax benefit recognized in the condensed consolidated statements of income for restricted stock awards was $917 thousand and $640 thousand for the three months ended March 31, 2018 and 2017, respectively. There was $2. 6 million of total unrecognized compensation cost related to restricted stock awards as of March 31, 2018, which is expected to be recognized over a weighted-average period of 1.87 years. There was $1.6 million of unrecognized compensation cost related to the 273,300 market and performance award shares discussed above as of March 31, 2018, which is expected to be recognized over a weighted-average period of 1.75 years.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2018
Accumulated Other Comprehensive Loss [Abstract]
Accumulated Other Comprehensive Loss	6. ACCUMULATED OTHER COMPREHENSIVE LOSS The following table sets forth the components of accumulated other comprehensive income (loss), net of tax where applicable (in thousands):     March 31, 2018 December 31, 2017   Unrealized losses on marketable securities $ (244) $ (160)  Accumulated other comprehensive loss $ (244) $ (160) 

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2018
Financial Instruments [Abstract]
Financial Instruments	7. FINANCIAL INSTRUMENTS  Certain financial assets and liabilities are accounted for at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The following fair value hierarchy prioritizes the inputs used to measure fair value:  Level 1 – Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis.  Level 2 – Pricing inputs are other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date. Level 2 includes those financial instruments that are valued using models or other valuation methodologies.  Level 3 – Pricing inputs include significant inputs that are generally less observable from objective sources. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value from the perspective of a market participant. The following tables represent cash and the available-for-sale securities adjusted cost, gross unrealized losses and fair value by significant investment category recorded as cash and cash equivalents or investment securities (in thousands):    March 31, 2018  Cost Unrealized Losses Accrued Interest Estimated Fair Value Cash & Cash Equivalents Investment Securities   Cash $ 39,005 $ - $ - $ 39,005 $ 39,005 $ -   Level 1:  Certificate of deposit 45,000 - - 45,000 45,000 -  Money market accounts 2,958 - - 2,958 2,958 -  Government & agency securities 4,136 (97) 17 4,056 - 4,056  52,094 (97) 17 52,014 47,958 4,056   Level 2:  Municipal bonds 18,257 (240) 205 18,222 - 18,222   Total $ 109,356 $ (337) $ 222 $ 109,241 $ 86,963 $ 22,278      December 31, 2017  Cost Unrealized Losses Accrued Interest Estimated Fair Value Cash & Cash Equivalents Investment Securities   Cash $ 28,630 $ - $ - $ 28,630 $ 28,630 $ -   Level 1:  Certificate of deposit 45,000 - - 45,000 45,000 -  Money market accounts 1,447 - - 1,447 1,447 -  Government & agency securities 5,342 (67) 13 5,288 - 5,288  51,789 (67) 13 51,735 46,447 5,288   Level 2:  Municipal bonds 18,404 (201) 266 18,469 - 18,469   Total $ 98,823 $ (268) $ 279 $ 98,834 $ 75,077 $ 23,757   The Company had a realized loss of $0 and $254 thousand for the three months ended March 31, 2018 and 2017, respectively. As of March 31, 2018 and 2017, gross unrealized losses related to individual securities that had been in a continuous loss position for 12 months or longer were not significant. The maturities of the Company’s investment securities generally range up to 5 years for municipal bonds and for government and agency securities.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Taxes [Abstract]
Income Taxes	8 . INCOME TAXES The Company reflected the effects of the Tax Cuts and Jobs Act (TCJA), in its 2017 financial statements. This included the effects of the change in the US Corporate tax rate from 35% to 21% on deferred tax assets and liabilities. The Company’s tax expense for the period ended March 31, 2018 is $ 2.7 million includes the reduction in the U.S. federal tax rate from 35% to 21%, effective for the Company’s 2018 tax year. The Company’s tax provision also reflects other changes as a result of the TCJA, including the impact of changes effecting the deductibility of certain executive compensation which increase the effective rate of 1.45% and elimination of the Domestic Manufacturer Deduction.

Summary of Significant Accoun16

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation - The accompanying unaudited condensed consolidated financial statements of Medifast, Inc. and its wholly-owned subsidiaries (the “Company,” “we,” “us,” or “our”) included herein have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”), for interim information and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for reporting on Form 10-Q. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. However, in the opinion of management, all adjustments consisting of normal, recurring adjustments considered necessary for a fair presentation of the financial position and results of operations have been included and management believes the disclosures that are made are adequate to make the information presented not misleading. The condensed consolidated balance sheet at December 31, 2017 has been derived from the audited consolidated financial statements at that date. The results of operations for the three months ended March 31, 2018 are not necessarily indicative of results that may be expected for the fiscal year ending December 31, 2018. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the 2017 audited consolidated financial statements and notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 (“2017 Form 10-K”).
Presentation of Financial Statements	Presentation of Financial Statements - The unaudited condensed consolidated financial statements included herein include the accounts of the Medifast, Inc. and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates - The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. Actual results could differ materially from those estimates.
Recent Accounting Pronouncements	Accounting Pronouncements Adopted in 2018 – In May 2014, the FASB issued ASU 2014-09 , Revenue from Contracts with Customers (Topic 606) . The new revenue recognition standard requires the Company to recognize revenue for the transfer of goods or services to customers for the amount the Company expects to be entitled to receive in exchange for those goods or services. The Company is required to identify the contract, identify the relevant performance obligations, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize the revenue when the entity satisfies a performance obligation. Companies have the option of using either a full retrospective or a modified retrospective approach to adopt the guidance. On January 1, 2018, the Company adopted the new revenue standard on a modified retrospective basis and recorded an after-tax transition adjustment to reduce retained earnings as of January 1, 2018 by $2.0 million. This is comprised of $5.6 million of revenue offset by $3.6 million of inventory costs, deferred shipping expense, credit card fees and income taxes. The results of ASU 606 primarily impact the Company’s timing of revenue recognition for product shipments, as product revenue is recognized upon customer receipt in lieu of at the time of shipment. The new standard requires more extensive revenue-related disclosures. As required by ASC 606, the impact of the adoption of the new revenue standard on our Condensed Consolidated Statements of Income and Condensed Consolidated Balance Sheets was as follows (in thousands):    Three months ended March 31, 2018  As Reported Balances without adoption of ASC 606 Effect of Change   Revenue $ 98,596 $ 97,254 $ 1,342  Cost of sales 23,788 23,521 (267)  Gross profit 74,808 73,733 1,075   Selling, general, and administrative 60,125 59,523 (602)   Income from operations 14,683 14,210 473   Other income (expense)  Interest income, net 249 249 -  Other income (expense) (1) (1) -  248 248 -   Income from operations before income taxes 14,931 14,458 473   Provision for income taxes 2,709 2,608 (101)   Net income $ 12,222 $ 11,850 $ 372   Earnings per share - basic $ 1.02 $ 0.99 $ 0.03   Earnings per share - diluted $ 1.01 $ 0.98 $ 0.03   Weighted average shares outstanding -  Basic 12,030 12,030  Diluted 12,139 12,139     March 31, 2018  As Reported Balances without adoption of ASC 606 Effect of Change   ASSETS  Accounts receivable, net $ 1,025 $ 92 $ 933  Inventory 17,288 16,624 664  Prepaid expenses and other current assets 3,577 3,491 86  Deferred tax assets 426 - 426   LIABILITIES  Accounts payable and accrued expenses 38,187 34,416 3,771  Deferred tax liabilities - 16 (16)   Stockholders' Equity  Retained earnings 108,243 109,889 (1,646)  The cumulative effect of the changes made to our January 1, 2018 Condensed Consolidated Balance Sheet from the modified retrospective adoption of ASC 606 was as follows (in thousands):    Balance at December 31, 2017 Adjustments due to ASC 606 Balance at January 1, 2018   ASSETS  Accounts receivable, net $ 576 $ 557 $ 1,133  Inventory 19,328 902 20,230  Prepaid expenses and other current assets 4,188 116 4,304  Deferred tax assets - 336 336   LIABILITIES  Accounts payable and accrued expenses 37,140 4,137 41,277  Deferred tax liabilities 208 (208) -   Stockholders' Equity  Retained earnings 103,762 (2,018) 101,744   Recent Accounting Pronouncements – We have considered all new accounting pronouncements and have concluded that there are no new pronouncements that may have a material impact on our results of operations, financial condition, or cash flows, based on current information, except for: ASU 2016-02, Leases (Topic 842) requires the rights and obligations of all leased assets with a term greater than 12 months to be presented on the balance sheet. The pronouncement is effective for fiscal years beginning after December 15, 2018. The Company currently expects that upon adoption of ASU 2016-02 right-to-use assets and lease liabilities will be recognized in the Company’s Consolidated Balance Sheet in amounts that will be material. Management is currently evaluating the effect that the provisions of ASU 2016-02 will have on the Company’s financial statements. ASU 2018-02, Income Statement Reporting - Comprehensive Income (Topic 220) allows the reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from tax effects resulting from the Tax Cuts and Jobs Act and will improve the usefulness of information reported to financial statement users. However, because the amendments only relate to the reclassification of the income tax effects of the Tax Cuts and Jobs Act, the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. The amendments in this Update are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Management is currently evaluating the effect that the provisions of ASU 2018-02 will have on the Company’s financial statements.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	As required by ASC 606, the impact of the adoption of the new revenue standard on our Condensed Consolidated Statements of Income and Condensed Consolidated Balance Sheets was as follows (in thousands):    Three months ended March 31, 2018  As Reported Balances without adoption of ASC 606 Effect of Change   Revenue $ 98,596 $ 97,254 $ 1,342  Cost of sales 23,788 23,521 (267)  Gross profit 74,808 73,733 1,075   Selling, general, and administrative 60,125 59,523 (602)   Income from operations 14,683 14,210 473   Other income (expense)  Interest income, net 249 249 -  Other income (expense) (1) (1) -  248 248 -   Income from operations before income taxes 14,931 14,458 473   Provision for income taxes 2,709 2,608 (101)   Net income $ 12,222 $ 11,850 $ 372   Earnings per share - basic $ 1.02 $ 0.99 $ 0.03   Earnings per share - diluted $ 1.01 $ 0.98 $ 0.03   Weighted average shares outstanding -  Basic 12,030 12,030  Diluted 12,139 12,139     March 31, 2018  As Reported Balances without adoption of ASC 606 Effect of Change   ASSETS  Accounts receivable, net $ 1,025 $ 92 $ 933  Inventory 17,288 16,624 664  Prepaid expenses and other current assets 3,577 3,491 86  Deferred tax assets 426 - 426   LIABILITIES  Accounts payable and accrued expenses 38,187 34,416 3,771  Deferred tax liabilities - 16 (16)   Stockholders' Equity  Retained earnings 108,243 109,889 (1,646)  The cumulative effect of the changes made to our January 1, 2018 Condensed Consolidated Balance Sheet from the modified retrospective adoption of ASC 606 was as follows (in thousands):    Balance at December 31, 2017 Adjustments due to ASC 606 Balance at January 1, 2018   ASSETS  Accounts receivable, net $ 576 $ 557 $ 1,133  Inventory 19,328 902 20,230  Prepaid expenses and other current assets 4,188 116 4,304  Deferred tax assets - 336 336   LIABILITIES  Accounts payable and accrued expenses 37,140 4,137 41,277  Deferred tax liabilities 208 (208) -   Stockholders' Equity  Retained earnings 103,762 (2,018) 101,744 

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2018
Inventories [Abstract]
Inventories	Inventories consisted of the following (in thousands):      March 31, 2018 December 31, 2017   Raw materials $ 4,283 $ 4,348  Packaging 1,247 1,185  Non-food finished goods 1,034 920  Finished goods 10,958 13,407  Reserve for obsolete inventory (234) (532)  Total $ 17,288 $ 19,328 

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share, Basic and Diluted	The following table sets forth the computation of basic and diluted EPS (in thousands, except per share data):    Three months ended March 31,  2018 2017   Numerator:  Net income $ 12,222 $ 6,145   Denominator:  Weighted average shares of common stock outstanding 12,030 11,901  Effect of dilutive common stock equivalents 109 108  Weighted average shares of common stock outstanding 12,139 12,009   Earnings per share - basic $ 1.02 $ 0.52   E arnings per share - diluted $ 1.01 $ 0.51 

Shared-based Compensation (Tabl

Shared-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Share-based Compensation [Abstract]
Schedule of Assumptions Used	The weighted average input assumptions used were as follows:     2018 2017   Expected term (in years) 6.4 6.0  Risk-free interest rate 2.64% 2.05%  Expected volatility 33.31% 38.33%  Dividend yield 2.88% 2.40%  
Schedule of Share-based Compensation, Stock Options, Activity	The following table is a summary of our stock option activity:     Three months ended March 31,  2018 2017  Shares Weighted-Average Exercise Price Shares Weighted-Average Exercise Price  (shares in thousands)  Outstanding at beginning of period 106 $ 31.18 129 $ 28.22  Granted 51 66.68 38 44.73  Exercised (21) 28.87 (21) 27.38  Forfeited - - (9) 38.18  Outstanding at end of the period 136 $ 44.79 137 $ 32.20  Exercisable at end of the period 60 $ 29.94 63 $ 28.15 
Restricted Stock Activity	The following table summarizes our restricted stock activity:     Three months ended March 31,  2018 2017  Shares Weighted-Average Grant Date Fair Value Shares Weighted-Average Grant Date Fair Value  (shares in thousands)  Outstanding at beginning of period 129 $ 32.15 215 $ 27.69  Granted 16 66.68 44 44.73  Vested (69) 28.35 (55) 25.94  Forfeited - - (6) 32.80  Outstanding at end of the period 76 $ 42.99 198 $ 31.79 

Accumulated Other Comprehensi21

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2018
Accumulated Other Comprehensive Loss [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table sets forth the components of accumulated other comprehensive income (loss), net of tax where applicable (in thousands):     March 31, 2018 December 31, 2017   Unrealized losses on marketable securities $ (244) $ (160)  Accumulated other comprehensive loss $ (244) $ (160) 

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Financial Instruments [Abstract]
Cash and Available for Sale Securities Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses, and Fair Value by Significant Investment Category	The following tables represent cash and the available-for-sale securities adjusted cost, gross unrealized losses and fair value by significant investment category recorded as cash and cash equivalents or investment securities (in thousands):    March 31, 2018  Cost Unrealized Losses Accrued Interest Estimated Fair Value Cash & Cash Equivalents Investment Securities   Cash $ 39,005 $ - $ - $ 39,005 $ 39,005 $ -   Level 1:  Certificate of deposit 45,000 - - 45,000 45,000 -  Money market accounts 2,958 - - 2,958 2,958 -  Government & agency securities 4,136 (97) 17 4,056 - 4,056  52,094 (97) 17 52,014 47,958 4,056   Level 2:  Municipal bonds 18,257 (240) 205 18,222 - 18,222   Total $ 109,356 $ (337) $ 222 $ 109,241 $ 86,963 $ 22,278      December 31, 2017  Cost Unrealized Losses Accrued Interest Estimated Fair Value Cash & Cash Equivalents Investment Securities   Cash $ 28,630 $ - $ - $ 28,630 $ 28,630 $ -   Level 1:  Certificate of deposit 45,000 - - 45,000 45,000 -  Money market accounts 1,447 - - 1,447 1,447 -  Government & agency securities 5,342 (67) 13 5,288 - 5,288  51,789 (67) 13 51,735 46,447 5,288   Level 2:  Municipal bonds 18,404 (201) 266 18,469 - 18,469   Total $ 98,823 $ (268) $ 279 $ 98,834 $ 75,077 $ 23,757  

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Narrative) (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Summary of Significant Accounting Policies [Abstract]
Allowance for doubtful accounts	$ 98
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	2,000
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Operating Results	5,600
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Operating Expenses	$ 3,600

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Impact of New Accounting Principles, Income) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 98,596	$ 70,622
Cost of sales	23,788	17,730
Gross profit	74,808	52,892
Selling, general, and administrative	60,125	44,283
Income from operations	14,683	8,609
Other income (expense)
Interest and dividend income, net	249	63
Other income (expense)	(1)	39
Nonoperating income (expense)	248	102
Income from continuing operations before income taxes	14,931	8,711
Provision for income taxes on continuing operations	2,709	2,566
Net income	$ 12,222	$ 6,145
Basic earnings per share
Earnings Per Share, Basic	$ 1.02	$ 0.52
Diluted earnings per share
Earnings Per Share, Diluted	$ 1.01	$ 0.51
Weighted average shares outstanding -
Basic	12,030	11,901
Diluted	12,139	12,009
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 97,254
Cost of sales	23,521
Gross profit	73,733
Selling, general, and administrative	59,523
Income from operations	14,210
Other income (expense)
Interest and dividend income, net	249
Other income (expense)	(1)
Nonoperating income (expense)	248
Income from continuing operations before income taxes	14,458
Provision for income taxes on continuing operations	2,608
Net income	$ 11,850
Basic earnings per share
Earnings Per Share, Basic	$ 0.99
Diluted earnings per share
Earnings Per Share, Diluted	$ 0.98
Weighted average shares outstanding -
Basic	12,030
Diluted	12,139
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 1,342
Cost of sales	(267)
Gross profit	1,075
Selling, general, and administrative	(602)
Income from operations	473
Other income (expense)
Income from continuing operations before income taxes	473
Provision for income taxes on continuing operations	(101)
Net income	$ 372
Basic earnings per share
Earnings Per Share, Basic	$ 0.03
Diluted earnings per share
Earnings Per Share, Diluted	$ 0.03

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Impact of New Accounting Principles, Balance Sheets) (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Current Assets
Accounts receivable, net	$ 1,025	$ 1,133	$ 576
Inventory	17,288	20,230	19,328
Prepaid expenses and other current assets	3,577	4,304	4,188
Deferred tax assets	426
Deferred tax assets	426	336
Current liabilities:
Accounts payable and accrued expenses	38,187	41,277	37,140
Other liabilities:
Deferred tax liabilities			208
Stockholders' Equity:
Retained earnings	108,243	$ 101,744	103,762
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Current Assets
Accounts receivable, net	92		576
Inventory	16,624		19,328
Prepaid expenses and other current assets	3,491		4,188
Current liabilities:
Accounts payable and accrued expenses	34,416		37,140
Other liabilities:
Deferred tax liabilities	16		208
Stockholders' Equity:
Retained earnings	109,889		103,762
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Current Assets
Accounts receivable, net	933		557
Inventory	664		902
Prepaid expenses and other current assets	86		116
Deferred tax assets	426
Deferred tax assets			336
Current liabilities:
Accounts payable and accrued expenses	3,771		4,137
Other liabilities:
Deferred tax liabilities	(16)		(208)
Stockholders' Equity:
Retained earnings	$ (1,646)		$ (2,018)

Inventories (Detail)

Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Inventories [Abstract]
Raw Materials	$ 4,283		$ 4,348
Packaging	1,247		1,185
Non-food Finished Goods	1,034		920
Finished Goods	10,958		13,407
Reserve for Obsolete Inventory	(234)		(532)
Inventory	$ 17,288	$ 20,230	$ 19,328

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Anti-dilutive options	4,690	4,531

Earnings Per Share (Earnings Pe

Earnings Per Share (Earnings Per Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net income	$ 12,222	$ 6,145
Denominator:
Weighted average shares of common stock outstanding	12,030	11,901
Effect of dilutive common stock equivalents	109	108
Weighted average shares of common stock outstanding	12,139	12,009
Basic earnings per share
Earnings per share	$ 1.02	$ 0.52
Diluted earnings per share
Earnings per share	$ 1.01	$ 0.51

Shared-based Compensation (Narr

Shared-based Compensation (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 805	$ 957
Weighted-average remaining contractual life of options oustanding	8 years 5 months 9 days
Aggregate intrinsic value of options outstanding	$ 6,600
Weighted-average remaining contractual life of options exercisable	7 years 3 months 7 days
Aggregate intrinsic value of options exercisable	$ 3,800
Proceeds from stock options exercised	62	568
Intrinsic value of options exercised	1,400	325
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total income tax benefit recognized related to restricted stock awards	917	640
Employee service share based compensation nonvested awards total compensation cost not yet recognized	$ 2,000
Compensation cost recognition weighted average period	1 year 10 months 13 days
Award vesting period	5 years
Share-based compensation arrangement, fair value of awards vested	$ 4,800	$ 2,400
Shares vested in period	69,000	55,000
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share based compensation nonvested awards total compensation cost not yet recognized	$ 1,100
Compensation cost recognition weighted average period	3 years 8 months 23 days
Award vesting period	3 years
Share-based compensation, shares authorized under stock option plans, exercise price range, lower range limit	$ 26.52
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value	17.79	$ 13.73
Share-based compensation, shares authorized under stock option plans, exercise price range, upper range limit	$ 66.68
Proceeds from stock options exercised	$ 62	$ 568
Share based compensation arrangement by share based payment award options expiration term	10 years
Options and Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 580	733
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share based compensation nonvested awards total compensation cost not yet recognized	$ 1,600
Compensation cost recognition weighted average period	1 year 9 months
Share based compensation expense	$ 73	$ 72
Share-based compensation arrangement shares to be issued	273,300
Shares vested in period	63,300	147,675
Performance Shares [Member] | Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	$ 152	$ 152
Share-based compensation arrangement shares to be issued	210,000	210,000

Shared-based Compensation (Sche

Shared-based Compensation (Schedule of Assumptions Used) (Detail)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation [Abstract]
Expected term (in years)	6 years 4 months 24 days	6 years
Risk-free interest rate	2.64%	2.05%
Expected volatility	33.31%	38.33%
Dividend yield	2.88%	2.40%

Shared-based Compensation (Sc31

Shared-based Compensation (Schedule of Share Based Compensation Stock Options Activity) (Detail) - Stock Option [Member] - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Outstanding Beginning Balance	106	129
Shares, Granted	51	38
Shares, Exercised	(21)	(21)
Shares, Forfeited		(9)
Shares, Outstanding Ending Balance	136	137
Shares, Exerciseable	60	63
Weighted-Average Exercise Price, Outstanding Beginning Balance	$ 31.18	$ 28.22
Weighted-Average Exercise Price, Granted	66.68	44.73
Weighted-Average Exercise Price, Exercised	28.87	27.38
Weighted-Average Exercise Price, Forfeited		38.18
Weighted-Average Exercise Price, Oustanding Ending Balance	44.79	32.20
Weighted-Average Exercise Price, Exerciseable	$ 29.94	$ 28.15

Shared-based Compensation (Summ

Shared-based Compensation (Summary of Restricted Stock Activity) (Detail) - Restricted Stock [Member] - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Shares
Unvested at beginning of period	129	215
Granted	16	44
Vested	(69)	(55)
Forfeited		(6)
Unvested at end of period	76	198
Weighted-Average Grant Date Fair Value
Unvested at beginning of period	$ 32.15	$ 27.69
Granted	66.68	44.73
Vested	28.35	25.94
Forfeited		32.80
Unvested at end of period	$ 42.99	$ 31.79

Accumulated Other Comprehensi33

Accumulated Other Comprehensive Loss (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Loss [Abstract]
Unrealized gains / (losses) on marketable securities	$ (244)	$ (160)
Accumulated other comprehensive loss	$ (244)	$ (160)

Financial Instruments (Narrativ

Financial Instruments (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Financial Instruments [Line Items]
Realized Gain (Loss) on Marketable Securities, Cost Method Investments, and Other Investments	$ 0	$ 254
US Treasury and Government Short-term Debt Securities [Member]
Financial Instruments [Line Items]
Available for Sale Securities Maturity Period	5 years

Financial Instruments (Cash and

Financial Instruments (Cash and Available for Sale Securities Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses, and Fair Value by Significant Investment Category) (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents and Marketable Securities [Line Items]
Cost	$ 109,356	$ 98,823
Unrealized Losses	(337)	(268)
Accrued Interest	222	279
Estimated Fair Value	109,241	98,834
Cash & Cash Equivalents	86,963	75,077	$ 53,970	$ 52,436
Investment Securities	22,278	23,757
Cash [Member]
Cash and Cash Equivalents and Marketable Securities [Line Items]
Cost	39,005	28,630
Estimated Fair Value	39,005	28,630
Cash & Cash Equivalents	39,005	28,630
Fair Value, Inputs, Level 1 [Member]
Cash and Cash Equivalents and Marketable Securities [Line Items]
Cost	52,094	51,789
Unrealized Losses	(97)	(67)
Accrued Interest	17	13
Estimated Fair Value	52,014	51,735
Cash & Cash Equivalents	47,958	46,447
Investment Securities	4,056	5,288
Fair Value, Inputs, Level 1 [Member] | Certificates of Deposit [Member]
Cash and Cash Equivalents and Marketable Securities [Line Items]
Cost	45,000	45,000
Estimated Fair Value	45,000	45,000
Cash & Cash Equivalents	45,000	45,000
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Cash and Cash Equivalents and Marketable Securities [Line Items]
Cost	2,958	1,447
Estimated Fair Value	2,958	1,447
Cash & Cash Equivalents	2,958	1,447
Fair Value, Inputs, Level 1 [Member] | Government and Agency Securities [Member]
Cash and Cash Equivalents and Marketable Securities [Line Items]
Cost	4,136	5,342
Unrealized Losses	(97)	(67)
Accrued Interest	17	13
Estimated Fair Value	4,056	5,288
Investment Securities	4,056	5,288
Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]
Cash and Cash Equivalents and Marketable Securities [Line Items]
Cost	18,257	18,404
Unrealized Losses	(240)	(201)
Accrued Interest	205	266
Estimated Fair Value	18,222	18,469
Investment Securities	$ 18,222	$ 18,469

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 21, 2017
Income Taxes [Abstract]
Effective tax rate, Statutory federal tax	21.00%		35.00%
Income Tax Expense (Benefit)	$ 2,709	$ 2,566
Effective tax rate, Share-based compensation	1.45%