Subsequent Event	3 Months Ended
Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Mist Acquisition On April 1, 2019, the Company completed the acquisition of Mist Systems, Inc. (“Mist”), a software company that provides cloud-managed wireless networks powered by artificial intelligence ("AI") for approximately $365.0 million in cash consideration, subject to adjustments for cash on hand, up to a certain limit, indebtedness, and certain other closing adjustments. A portion of the consideration includes certain share-based awards attributable to services prior to the acquisition. Credit Facility In April 2019, the Company entered into a new credit agreement with certain institutional lenders that provides for a five-year $500.0 million unsecured revolving credit facility (the "Revolving Credit Facility"), with an option to increase the Revolving Credit Facility by up to an additional $200.0 million, subject to the lenders' approval. The Revolving Credit Facility will terminate in April 2024, subject to two one-year maturity extension options, on the terms and conditions set forth in the Revolving Credit Facility. Dividend Declaration On April 25, 2019, the Company announced that the Board declared a cash dividend of $0.19 per share of common stock to be paid on June 24, 2019 to stockholders of record as of the close of business on June 3, 2019. Stock Repurchase Activities The Board also authorized the Company to enter into an ASR for an amount up to $300.0 million under the 2018 Stock Repurchase Program. On April 29, 2019, the Company entered into an ASR with a financial institution, to repurchase an aggregate of approximately $300.0 million of the Company’s outstanding common stock. The Company made an up-front payment of $300.0 million pursuant to the ASR and received and retired an initial 8.6 million shares of the Company’s common stock for an aggregate price of $240.0 million based on the market value of the Company’s common stock on the date of the transaction. The Company has an aggregate of $1.0 billion of authorized funds remaining under the 2018 Stock Repurchase Program, as of the filing of this Quarterly Report on Form 10-Q. Future share repurchases under the 2018 Stock Repurchase Program will be subject to a review of the circumstances at that time and will be made from time to time in private transactions or open market purchases as permitted by securities laws and other legal requirements. The Company's 2018 Stock Repurchase Program may be discontinued at any time. Restructuring In April 2019, the Company amended the 2019 Restructuring Plan to implement certain additional organizational changes resulting in a realignment of the Company's workforce. As a result, the Company expects to record severance charges of approximately $6.0 million to $7.5 million related to headcount reductions in the second quarter of 2019.

Subsequent Event

Mist Acquisition

On April 1, 2019, the Company completed the acquisition of Mist Systems, Inc. (“Mist”), a software company that provides cloud-managed wireless networks powered by artificial intelligence ("AI") for approximately $365.0 million in cash consideration, subject to adjustments for cash on hand, up to a certain limit, indebtedness, and certain other closing adjustments. A portion of the consideration includes certain share-based awards attributable to services prior to the acquisition.

Credit Facility

In April 2019, the Company entered into a new credit agreement with certain institutional lenders that provides for a five-year $500.0 million unsecured revolving credit facility (the "Revolving Credit Facility"), with an option to increase the Revolving Credit Facility by up to an additional $200.0 million, subject to the lenders' approval. The Revolving Credit Facility will terminate in April 2024, subject to two one-year maturity extension options, on the terms and conditions set forth in the Revolving Credit Facility.

Dividend Declaration

On April 25, 2019, the Company announced that the Board declared a cash dividend of $0.19 per share of common stock to be paid on June 24, 2019 to stockholders of record as of the close of business on June 3, 2019.

Stock Repurchase Activities

The Board also authorized the Company to enter into an ASR for an amount up to $300.0 million under the 2018 Stock Repurchase Program.

On April 29, 2019, the Company entered into an ASR with a financial institution, to repurchase an aggregate of approximately $300.0 million of the Company’s outstanding common stock. The Company made an up-front payment of $300.0 million pursuant to the ASR and received and retired an initial 8.6 million shares of the Company’s common stock for an aggregate price of $240.0 million based on the market value of the Company’s common stock on the date of the transaction. The Company has an aggregate of $1.0 billion of authorized funds remaining under the 2018 Stock Repurchase Program, as of the filing of this Quarterly Report on Form 10-Q.

Future share repurchases under the 2018 Stock Repurchase Program will be subject to a review of the circumstances at that time and will be made from time to time in private transactions or open market purchases as permitted by securities laws and other legal requirements. The Company's 2018 Stock Repurchase Program may be discontinued at any time.

Restructuring

In April 2019, the Company amended the 2019 Restructuring Plan to implement certain additional organizational changes resulting in a realignment of the Company's workforce. As a result, the Company expects to record severance charges of approximately $6.0 million to $7.5 million related to headcount reductions in the second quarter of 2019.