The Company and Summary of Significant Accounting Policies and Estimates - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash flows from operating activities	$ 256,084	$ 240,647
Cash flow from financing activities	$ 124,214	149,556
Cumulative-effect adjustment to retained earnings			$ 57,205
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment to retained earnings			53,912
Accounting Standards Update 2016-09, Excess Tax Benefit Component Increase to Operating Cash FLows
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash flows from operating activities		6,400
Gross excess tax benefits			75,200
Tax benefit valuation allowance			18,000
Accounting Standards Update 2016-09, Excess Tax Benefit Component Increase to Operating Cash FLows | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment to retained earnings			57,200
Accounting Standards Update 2016-09, Excess Tax Benefit Component Decrease to Financing Cash Flows
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash flow from financing activities		$ 6,400
Accounting Standards Update 2016-09, Forfeiture Rate Component | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change on retained earning			$ 3,300