Shareholder's Equity (Narrative) (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares	Mar. 31, 2016 USD ($) installment $ / shares shares	Mar. 31, 2015 USD ($) $ / shares shares
Common Stock:
Repurchase of common stock, shares		77,780	67,000
Repurchase of common stock | $		$ 5,700	$ 3,700
Mandatory Convertible Preferred Stock
Preferred stock dividends | $		$ (2,264)	$ (2,264)
Preferred Stock, Shares Outstanding	1,725,000	1,725,000
Stock Incentive Plans:
Number of shares authorized for grant under share incentive plan		1,200,000
Shares available for future grants/issuance under stock incentive plan		416,463
Unrecognized compensation cost on non vested awards | $		$ 49,100
Weighted average period		1 year 3 months
Number of units granted		566,763
Grant date value of common stock | $ / shares		$ 73.98
Stock Options [Member]
Stock Incentive Plans:
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
Options term		10 years
Employees [Member] | Restricted Stock [Member]
Stock Incentive Plans:
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
Number of installments in restricted stock granted. | installment		3
Mandatory Convertible Preferred Stock [Member]
Stock Incentive Plans:
Number of anti-dilutive options		3,100,000	3,200,000
Stock Options [Member]
Stock Incentive Plans:
Number of anti-dilutive options		0	0
Common Stock [Member]
Issuance of stock (in shares)	5,835,000
Issuance of stock, price per share | $ / shares	$ 80.00
Stock offering expenses | $	$ 19,100
Mandatory Convertible Preferred Stock [Member]
Mandatory Convertible Preferred Stock
Dividend rate		5.25%
Initial liquidation preference (usd per share) | $ / shares		$ 100
Consecutive trading day		20 days
Dividends declared (usd per share) | $ / shares		$ 1.3125	$ 1.3125
Minimum [Member] | Mandatory Convertible Preferred Stock [Member]
Mandatory Convertible Preferred Stock
Conversion rate		1.8141
Maximum [Member] | Mandatory Convertible Preferred Stock [Member]
Mandatory Convertible Preferred Stock
Conversion rate		2.2222
Performance-based Restricted Stock Units [Member]
Stock Incentive Plans:
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Number of units granted		73,003
Grant date value of common stock | $ / shares		$ 73.98
Performance goal period for vesting		1 year
Projected vesting percentage		100.00%
Performance-based Restricted Stock Units [Member] | Minimum [Member]
Stock Incentive Plans:
Projected vesting percentage		0.00%
Performance-based Restricted Stock Units [Member] | Maximum [Member]
Stock Incentive Plans:
Projected vesting percentage		150.00%