Stockholders' Equity (Common Stock Shares Activity) (Details) (USD $)	0 Months Ended	9 Months Ended	12 Months Ended
Nov. 05, 2014	Dec. 31, 2014	Mar. 31, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock, shares, beginning of period		609,625us-gaap_TreasuryStockShares	405,843us-gaap_TreasuryStockShares
Repurchase of common stock	1,000,000us-gaap_TreasuryStockSharesAcquired	1,377,001us-gaap_TreasuryStockSharesAcquired	203,782us-gaap_TreasuryStockSharesAcquired
Treasury stock, shares, end of period		1,986,626us-gaap_TreasuryStockShares	609,625us-gaap_TreasuryStockShares
Repurchase of common stock, price per share	$ 25.10
Common stock, Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares issued, beginning of period		143,962,073	136,457,444
Issuance of common stock		1,315,400	1,047,160
Stock options exercised		3,099,729	5,299,501
Share exchange		1,517,951	1,157,968
Common stock, shares issued, end of period		149,895,153	143,962,073
Non-voting common stock, Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares issued, beginning of period		582,080	1,451,600
Share exchange		(582,080)	(869,520)
Common stock, shares issued, end of period		0	582,080
Restricted common stock, Class C
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares issued, beginning of period		935,871	1,224,319
Share exchange		(935,871)	(288,448)
Common stock, shares issued, end of period		0	935,871
Special voting common stock, Class E
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares issued, beginning of period		4,424,814	7,478,522
Stock options exercised		(2,573,225)	(3,053,708)
Common stock, shares issued, end of period		1,851,589	4,424,814

Stock ssued During Period Shares, Share Exchange

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Number of shares issued which are neither cancelled nor held in the treasury.

+ References

No definition available.

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Number of new stock issued during the period.

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- Definition

Number of share options (or share units) exercised during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

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-Paragraph 29, 30

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Total cost of shares repurchased divided by the total number of shares repurchased.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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-Publisher FASB

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-Section S99

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Number of shares that have been repurchased during the period and are being held in treasury.

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