Total stock-based compensation expense based on actual achievement of performance goals.

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The number of available shares expired under the plan.

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Price target for market-based awards.

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Maximum stock-based compensation expense assuming the achievement of highest level of performance goals.

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Number of individual price target.

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The highest value of shares an employee can purchase under the plan per period.

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Total amount of performance metrics that are able to be met under the stock plan.

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Price of a single share of a number of saleable stocks that the employee pays to the company upon vesting of the shares.

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Number of individual tranches in a single share-based payment award plan.

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Period after an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, that restricts an employee to sell such award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Represents the intrinsic value for stock purchased under the employee stock purchase plan.

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Total MSUs earned under the program.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Intrinsic value of equity-based compensation awards vested. Excludes stock and unit options.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Note 7 - Stock-based Compensation (Details Textual)		1 Months Ended										3 Months Ended	12 Months Ended
Note 7 - Stock-based Compensation (Details Textual)	Nov. 12, 2014 shares	Feb. 28, 2017 USD ($) shares	Jul. 31, 2016 $ / shares shares	Mar. 31, 2016 shares	Feb. 29, 2016 USD ($) $ / shares shares	Dec. 31, 2015 $ / shares shares	Feb. 28, 2015 shares	Apr. 30, 2014 shares	Mar. 31, 2014 shares	Feb. 28, 2014 shares	Feb. 28, 2013 USD ($) shares	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) $ / shares shares	Nov. 13, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period													1,349,000	1,198,000	1,287,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period													336,000	66,000	49,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value \| $													$ 3,700,000	$ 18,600,000	$ 17,300,000
Proceeds from Stock Options Exercised \| $													1,344,000	7,744,000	11,941,000
Proceeds from Stock Plans \| $													2,463,000	2,227,000	2,078,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested \| $													62,900,000	$ 49,200,000	$ 28,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding \| $													$ 332,900,000
Share Price \| $ / shares													$ 81.93
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized \| $													$ 84,800,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition													4 years
Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period													133,000	271,000	335,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period													27,000	42,000	32,000
2016 Executive PSUs and 2016 Non-executive PSUs [Member]
Share Price \| $ / shares			$ 70.98		$ 58.98
Purchase Price Per Share \| $ / shares					$ 20
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term			2 years 109 days		2 years 219 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate			29.60%		31.10%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate			0.70%		0.90%
2015 MPSUs [Member]
Share Price \| $ / shares						$ 61.35								$ 61.35
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period						127,000
PSUs Maximum Earn-Out						500.00%
Maximum Stock Compensation Costs \| $													$ 24,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate														33.20%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate														1.30%
Number of MPSU Tranches						4
Share-based Compensation Arrangement by Share-based Payment Award, Post-Award Vesting Period, Restriction Period on Sales						2 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions														7.80%
2015 MPSUs [Member] \| Share-based Compensation Award, Tranche One [Member]
Maximum Stock Compensation Costs \| $													8,300,000
Number of Price Targets						5
2015 MPSUs [Member] \| Second, Third, and Fourth Tranches [Member]
Number of Price Targets						5
Total number of performance conditions						6
2015 MPSUs [Member] \| Share-based Compensation Award, Tranche Two [Member]
Maximum Stock Compensation Costs \| $													4,500,000
2015 MPSUs [Member] \| Share-based Compensation Award, Tranche Three [Member]
Maximum Stock Compensation Costs \| $													5,200,000
2015 MPSUs [Member] \| Share-based Compensation Award, Tranche Four [Member]
Maximum Stock Compensation Costs \| $													6,600,000
2015 MPSUs [Member] \| Minimum [Member] \| Share-based Compensation Award, Tranche One [Member]
Market Awards Price Targets \| $ / shares						$ 71.36
2015 MPSUs [Member] \| Maximum [Member] \| Share-based Compensation Award, Tranche One [Member]
Market Awards Price Targets \| $ / shares						$ 95.57
2015 Executive PSUs [Member]
PSUs Maximum Earn-Out							300.00%
2015 Executive PSUs [Member] \| Subsequent Event [Member]
Total PSU Earned		432,000
Actual Stock Compensation Costs \| $		$ 21,000,000
2015 Non-Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							2 years
2015 Non-Executive PSUs [Member] \| Subsequent Event [Member]
Total PSU Earned		118,000
Actual Stock Compensation Costs \| $		$ 5,700,000
2015 Non-Executive PSUs [Member] \| Minimum [Member]
PSUs Maximum Earn-Out							200.00%
2015 Non-Executive PSUs [Member] \| Maximum [Member]
PSUs Maximum Earn-Out							300.00%
The 2014 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										2 years
PSUs Maximum Earn-Out										300.00%
Total PSU Earned					694,000
Actual Stock Compensation Costs \| $					$ 20,700,000
The 2014 Executive PSUs [Member] \| Share-based Compensation Award, Tranche One [Member] \| Vesting in the First Quarter of 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										50.00%
The 2014 Non-Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								2 years
Total PSU Earned					103,000
Actual Stock Compensation Costs \| $					$ 3,700,000
The 2014 Non-Executive PSUs [Member] \| Share-based Compensation Award, Tranche One [Member] \| Vesting in the Second Quarter of 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								50.00%
The 2014 Non-Executive PSUs [Member] \| Minimum [Member]
PSUs Maximum Earn-Out								200.00%
The 2014 Non-Executive PSUs [Member] \| Maximum [Member]
PSUs Maximum Earn-Out								300.00%
The 2013 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period											2 years
PSUs Maximum Earn-Out											300.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage											50.00%
Total PSU Earned											622,000
Actual Stock Compensation Costs \| $											$ 15,000,000
The 2013 Non-Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period											2 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage											50.00%
Total PSU Earned											154,000
Actual Stock Compensation Costs \| $											$ 3,000,000
The 2013 Non-Executive PSUs [Member] \| Minimum [Member]
PSUs Maximum Earn-Out											200.00%
The 2013 Non-Executive PSUs [Member] \| Maximum [Member]
PSUs Maximum Earn-Out											300.00%
The 2013 Executive MSUs [Member]
Share Price \| $ / shares																$ 31.73
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period																5 years
PSUs Maximum Earn-Out																500.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate																38.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate																1.60%
Number of Price Targets																5
Actual Stock Compensation Costs \| $																$ 38,200,000
Total MSUE arned																1,800,000
The 2013 Executive MSUs [Member] \| Minimum [Member]
Market Awards Price Targets \| $ / shares																$ 40
The 2013 Executive MSUs [Member] \| Maximum [Member]
Market Awards Price Targets \| $ / shares																$ 56
Employee Stock Option [Member]
Proceeds from Stock Options Exercised \| $													$ 1,300,000	$ 7,700,000	$ 11,900,000
Chief Financial Officer [Member] \| Restricted Stock Units (RSUs) [Member] \| Selling, General and Administrative Expenses [Member]
Share-based Compensation Adjustment \| $												$ 2,900,000
Chief Financial Officer [Member] \| 2016 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period				32,000
Chief Financial Officer [Member] \| 2015 MPSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period				13,000
Chief Financial Officer [Member] \| 2015 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				19,000
Chief Financial Officer [Member] \| The 2014 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				37,000
Chief Financial Officer [Member] \| The 2013 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				18,000
Chief Financial Officer [Member] \| The 2013 Executive MSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				36,000
Employees [Member] \| Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period													4 years
Director [Member] \| Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period													1 year
Executive Officer [Member] \| 2016 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			12,000		285,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period					2 years
PSUs Maximum Earn-Out					300.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage					50.00%
Maximum Stock Compensation Costs \| $													$ 31,800,000
Executive Officer [Member] \| PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period							172,000			252,000	220,000
Executive Officer [Member] \| 2015 Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							2 years
Executive Officer [Member] \| 2015 Executive PSUs [Member] \| Share-based Compensation Award, Tranche One [Member] \| Vesting in The First Quarter of 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							50.00%
Non-Executive Employees [Member] \| 2016 Non-Executive PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period					64,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period					2 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage					50.00%
Maximum Stock Compensation Costs \| $					$ 6,000,000
Non-Executive Employees [Member] \| 2016 Non-Executive PSUs [Member] \| Minimum [Member]
PSUs Maximum Earn-Out, Second Tier					200.00%
Non-Executive Employees [Member] \| 2016 Non-Executive PSUs [Member] \| Maximum [Member]
PSUs Maximum Earn-Out, First Tier					300.00%
Non-Executive Employees [Member] \| PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period							58,000	61,000			91,000
2015 Non-Executive PSUs [Member] \| Share-based Compensation Award, Tranche One [Member] \| Vesting in The First Quarter of 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							50.00%
Executive Officers and Non-Executive Employees [Member] \| The 2013 Executive MSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period																360,000
The2014 Plan [Member]
Share-basedCompensation Arrangement by Share-based Payment Award, Other Than Options, Percent Increases in Period									5.00%
Share-based Compensation Arrangement by Share-based Payment Award, Automatic Increase Shares									2,400,000
Expired Shares under Plan	2,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																	5,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant													3,800,000
The 2004 Employee Stock Purchase Plan [Member]
Share-basedCompensation Arrangement by Share-based Payment Award, Other Than Options, Percent Increases in Period													2.00%
Share-based Compensation Arrangement by Share-based Payment Award, Automatic Increase Shares													1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant													4,600,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized \| $													$ 93,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee													2,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares per Employee Value													25,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans													53,000	56,000	78,000
Employee Stock Purchase Plan Shares Issued, Intrinsic Value \| $													$ 1,000,000	$ 600,000	$ 900,000
Proceeds from Stock Plans \| $													$ 2,500,000	$ 2,200,000	$ 2,100,000