Employee Stock-Based Compensation and Benefit Plans (Narrative) (Details) $ / shares in Units, $ in Thousands		1 Months Ended				3 Months Ended	12 Months Ended			13 Months Ended	17 Months Ended
		Mar. 31, 2016 $ / shares shares	Jan. 31, 2016 $ / shares shares	Mar. 31, 2015 $ / shares shares	Mar. 31, 2014 shares	Mar. 31, 2016	Dec. 31, 2016 USD ($) installment plan $ / shares shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) $ / shares	Mar. 31, 2015	May 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plans offered | plan							1
Stock-based compensation | $	[1]						$ 184,788	$ 147,368	$ 169,287
Deferred tax asset related to stock-based compensation | $							61,500	46,100	46,900
Tax benefit from compensation expense | $							$ 66,100	52,700	43,900
401(k) Benefit Plan [Abstract]
Maximum annual contribution per employee (as a percent)							90.00%
Contribution per dollar of employee contribution							50.00%
Matching percent							3.00%
Defined Contribution Plan, Cost Recognized | $							$ 17,900	15,900	14,400
Employer contributions, vesting period											4 years
Employer contributions, annual vesting rate											25.00%
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period		3 years
Maximum target shareholder return (percent)		10.00%
Maximum share cap based on target shareholder return (percent)		100.00%
Minimum target shareholder return (percent)		5.00%
Minimum share cap based on target shareholder return (percent)		200.00%
Target shareholder return maximum to attain 200% (percent)		30.00%
Period to determine actual stock grant following end of interim measurement period		60 days
Interim measurement period		18 months
Share cap based on interim measurement period (percent)		33.00%
Period to determine actual stock grant following end of performance period		60 days
Non-vested stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation | $							$ 9,600	$ 1,400
Non-vested stock unit awards granted to senior level employees (shares)							118,588	102,851
Total unrecognized compensation cost related to stock-based compensation | $							$ 5,300
Total unrecognized compensation cost recognition period (in years)							2 years
Non-vested stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period							1 year
Non-vested stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period							3 years
Market and service condition stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested stock unit awards granted to senior level employees (shares)		234,816		393,464	378,022
Performance period							3 years
Period to determine actual stock grant following end of performance period							60 days
Maximum percentage of market and service condition stock units that will ultimately vest							200.00%
Minimum overperformance percentage against benchmark index return for maximum stock issuance, percentage							40.00%
Maximum underperformance against benchmark index return before company discontinues issuance of stock, percentage (more than 20%)							20.00%
Percent of award issued if return is negative but benchmark index is met							75.00%
Non-vested stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation | $							$ 166,400	$ 135,900	$ 143,100
Non-vested stock unit awards granted to senior level employees (shares)							2,538,589
Number of shares represented by each award upon vesting (shares)							1
Expected volatility rate, calculation basis, period						3 years				2 years 9 months 4 days
Granted (in dollars per share) | $ / shares		$ 66.18	$ 49.68	$ 61.01			$ 76.27		$ 56.94
Share-based compensation award, stock vesting period, monthly installments | installment							12
Maximum non-vested stock units issuable as percent of base number set forth in award agreement (percent)							100.00%
Fair value of awards released | $							$ 163,800	$ 132,900	$ 118,300
Total unrecognized compensation cost related to stock-based compensation | $							$ 223,400
Total unrecognized compensation cost recognition period (in years)							2 years 22 days
Non-vested stock | Annual vesting on each anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage							33.33%
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance under the Plan (shares)							29,000,000
Shares reserved for issuance under the Plans (shares)							20,068,672
Shares available for grant under the 2014 Equity Incentive Plan (shares)							15,584,300
2005 ESPP Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan, total shares issued under plan (shares)							3,872,661
Stock-based compensation | $									$ 5,200
2015 ESPP Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance under the Plan (shares)							16,000,000
Employee Stock Purchase Plan, payment period							6 months
Employee Stock Purchase Plan, maximum number of shares per period that employees can purchase (shares)							12,000
Employee Stock Purchase Plan, lower of purchase price offered on either first or last day of payment period as a percentage of fair market value (percent)							85.00%
Employee Stock Purchase Plan, employee disqualification, ownership percent of outstanding stock							5.00%
Employee Stock Purchase Plan, total shares issued under plan (shares)							974,830
Expected volatility rate, calculation basis, period							6 months	6 months
2015 ESPP Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan, option to purchase shares through payroll deduction, payroll deduction amount per pay period per employee, as a percentage of base pay							1.00%
2015 ESPP Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan, option to purchase shares through payroll deduction, payroll deduction amount per pay period per employee, as a percentage of base pay							10.00%
Employee Stock Purchase Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation | $							$ 8,800	$ 7,600
Chief Executive Officer | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested stock unit awards granted to senior level employees (shares)			220,235

[1] Represents expenses presented to management on a consolidated basis only and not allocated to the operating segments.