Financial Statement Presentation - Effects of New Accounting Standards on Previously Reported Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Jun. 30, 2016	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Cash Provided by Operating Activities	$ 269,378	$ 67,112
Net Cash Provided by Financing Activities	$ (14,683)	565,751
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Cash Provided by Operating Activities		67,112	$ 152,290	$ 257,705	$ 398,441	$ 749,598
Net Cash Provided by Financing Activities		565,751	492,428	463,115	453,805	223,296
As Reported | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Cash Provided by Operating Activities		62,090	147,244	252,649	392,377	740,737
Net Cash Provided by Financing Activities		$ 570,773	$ 497,474	$ 468,171	$ 458,869	$ 232,157