Shareholder's Equity (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 02, 2014	Aug. 29, 2014	Jul. 16, 2014	Aug. 09, 2013	Apr. 24, 2012
Common Stock:
Stock repurchased program authorized by the board of directors							$ 40,000,000.0	$ 40,000,000.0
Amount remaining under stock repurchase plan	27,100,000
Mandatory Convertible Preferred Stock
Preferred stock dividends	4,503,000	0	0
Stock Incentive Plans:
Restricted marketable securities	3,000,000
Excess tax benefit from share-based compensation	3,177,000	7,247,000	1,784,000
Number of shares authorized for grant under share incentive plan	1,200,000
Shares available for future grants/issuance under stock incentive plan	1,132,862
Unrecognized compensation cost on non vested awards	8,400,000
Weighted average period	1 year 2 months 12 days
Stock Repurchased Under Repurchase Program [Member]
Common Stock:
Repurchase of common stock, shares		1,154,378
Repurchase of common stock		42,700,000
Average price per share		$ 36.93
Stock Repurchased To Cover Employee Tax Withholdings [Member]
Common Stock:
Repurchase of common stock, shares	100,720	102,252
Repurchase of common stock	4,600,000	3,300,000
Stock Options [Member]
Stock Incentive Plans:
Award vesting period	4 years
Options term	10 years
Outside Directors [Member] | Restricted Stock [Member]
Stock Incentive Plans:
Award vesting period	1 year
Employees [Member] | Restricted Stock [Member]
Stock Incentive Plans:
Award vesting period	4 years
Number of installments in restricted stock granted.	3
Stock Options [Member]
Stock Incentive Plans:
Number of anti-dilutive options	0	0	20,000
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of stock (in shares)				9,775,000
Issuance of stock, price per share				$ 45.00
Stock offering expenses				18,500,000
Mandatory Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of stock (in shares)				1,725,000
Issuance of stock, price per share				$ 100.00
Stock offering expenses				5,900,000
Mandatory Convertible Preferred Stock
Dividend rate	5.25%
Initial liquidation preference (usd per share)	$ 100
Consecutive trading day	20 days
Dividends declared (usd per share)					$ 1.2979
Preferred stock dividends					2,200,000
Future preferred stock dividends (usd per share)	$ 1.3125
Future preferred stock dividends					$ 2,300,000
Sheridan Healthcare [Member] | Common Stock [Member]
Common Stock:
Shares of common stock issued for acquisition						5,713,909
Minimum [Member] | Mandatory Convertible Preferred Stock [Member]
Mandatory Convertible Preferred Stock
Conversion rate (shares)	1.8141
Maximum [Member] | Mandatory Convertible Preferred Stock [Member]
Mandatory Convertible Preferred Stock
Conversion rate (shares)	2.2222