Share Based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Share-based expense (net of estimated forfeitures):
Total share-based expense	$ 1,700,000	$ 1,800,000	$ 3,700,000	$ 3,400,000
Total recognized tax benefit	(500,000)	(600,000)	(1,000,000)	(1,100,000)
Share-based expense (net of tax)	1,200,000	1,200,000	2,700,000	2,300,000
2007 Plan [Member]
Activity in the Company's stock option plans [Roll Forward]
Outstanding, beginning of period (in shares)			1,332,000
Granted (in shares)			286,000
Exercised (in shares)			(85,000)
Forfeited and expired (in shares)			(10,000)
Outstanding, end of period (in shares)	1,523,000		1,523,000
Stock option plans, additional disclosures [Abstract]
Exercisable, end of period (in shares)	810,000		810,000
Predecessor Plan 1998 Employee Plan [Member]
Activity in the Company's stock option plans [Roll Forward]
Outstanding, beginning of period (in shares)			1,055,000
Granted (in shares)			0
Exercised (in shares)			(171,000)
Forfeited and expired (in shares)			(8,000)
Outstanding, end of period (in shares)	876,000		876,000
Stock option plans, additional disclosures [Abstract]
Exercisable, end of period (in shares)	876,000		876,000
Predecessor Plan 1998 Directors' Plan [Member]
Activity in the Company's stock option plans [Roll Forward]
Outstanding, beginning of period (in shares)			190,000
Granted (in shares)			0
Exercised (in shares)			(17,000)
Forfeited and expired (in shares)			0
Outstanding, end of period (in shares)	173,000		173,000
Stock option plans, additional disclosures [Abstract]
Exercisable, end of period (in shares)	173,000		173,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant-date fair value (in dollars per share)			$ 8.92
Weighted average fair value assumptions [Abstract]
Volatility rate (in hundredths)			29.10%
Risk-free interest rate (in hundredths)			2.40%
Dividend yield (in hundredths)			3.10%
Expected term (in years)			6.0
Activity in the Company's stock option plans [Roll Forward]
Outstanding, beginning of period (in shares)			2,577,000
Granted (in shares)			285,569
Exercised (in shares)			(273,000)
Forfeited and expired (in shares)			(18,000)
Outstanding, end of period (in shares)	2,572,000		2,572,000
Stock option plans, additional disclosures [Abstract]
Outstanding, weighted average exercise price, beginning of period (in dollars per share)			$ 37.10
Granted, weighted average exercise price (in dollars per share)	$ 40.63		$ 40.63
Exercised, weighted average exercise price (in dollars per share)	$ 29.69		$ 29.69
Forfeited and expired, weighted average exercise price (in dollars per share)			$ 45.95
Outstanding, weighted average exercise price, end of period (in dollars per share)	$ 38.22		$ 38.22
Outstanding, weighted average contractual life, end of period (in years)	5.7		5.7
Outstanding, aggregate intrinsic value, end of period	25,942,000		25,942,000
Exercisable, end of period (in shares)	1,859,000		1,859,000
Exercisable, weighted average exercise price, end of period (in dollars per share)	$ 39.88		$ 39.88
Exercisable, weighted average contractual life, end of period (in years)			4.7
Exercisable, aggregate intrinsic value, end of period	15,881,000		15,881,000
Share-based expense (net of estimated forfeitures):
Total share-based expense	500,000	400,000	1,000,000	800,000
2007 Plan Restricted Stock Units [Member]
Non-vested restricted stock unit activity [Roll Forward]
Outstanding, beginning of period (in shares)			330,000
Granted (in shares)			253,000
Vested (in shares)			(175,000)
Canceled (in shares)			(3,000)
Outstanding, end of period (in shares)	405,000		405,000
Non-vested restricted stock unit activity, additional disclosures [Abstract]
Outstanding, weighted average grant-date fair value, beginning of period (in dollars per share)			$ 31.15
Granted, weighted average grant-date fair value (in dollars per share)			$ 38.70
Vested, weighted average grant-date fair value (in dollars per share)			$ 32.24
Canceled, weighted average grant-date fair value (in dollars per share)	$ 35.51		$ 35.51
Outstanding, weighted average grant-date fair value, end of period (in dollars per share)	$ 35.37		$ 35.37
Vesting period of time-based awards (in years)			3Y
Minimum vesting period of performance-based awards, provided performance targets are achieved (in years)			3Y
Share-based expense (net of estimated forfeitures):
Total share-based expense	$ 1,200,000	$ 1,400,000	$ 2,700,000	$ 2,600,000