Capital Stock, Stock Awards, and Stock Options (Narrative) (Details) (USD $)	12 Months Ended					12 Months Ended														1 Months Ended	12 Months Ended							12 Months Ended	24 Months Ended
	Dec. 31, 2012	Dec. 31, 2011 year	Jan. 02, 2011	Jan. 03, 2010	Dec. 28, 2008	Dec. 31, 2011 Education [Member]	Dec. 31, 2010 Education [Member]	Dec. 31, 2009 Education [Member]	Dec. 31, 2012 Stock Option Plan [Member]	Dec. 31, 2011 Stock Option Plan [Member] year	Jan. 02, 2011 Stock Option Plan [Member]	Jan. 03, 2010 Stock Option Plan [Member]	Dec. 31, 2011 Stock Option Plan [Member] Exercise price above fair market value of common stock [Member]	Dec. 31, 2011 Stock Awards [Member] year	Jan. 02, 2011 Stock Awards [Member]	Jan. 03, 2010 Stock Awards [Member]	Dec. 31, 2011 Kaplan Stock Option [Member]	Dec. 31, 2010 Kaplan Stock Option [Member]	Dec. 31, 2009 Kaplan Stock Option [Member]	Dec. 31, 2011 Kaplan Stock Option [Member] Senior Manager [Member]	Dec. 31, 2011 Class A Common Stock [Member]	Jan. 02, 2011 Class A Common Stock [Member]	Dec. 31, 2011 Class B Common Stock [Member]	Jan. 02, 2011 Class B Common Stock [Member]	Jan. 03, 2010 Class B Common Stock [Member]	Oct. 02, 2011 Class B Common Stock [Member]	Dec. 31, 2011 Class B Common Stock [Member] Stock Option Plan [Member]	Dec. 31, 2011 Kaplan Restricted Stock [Member]	Dec. 31, 2010 Kaplan Restricted Stock [Member] Senior Manager [Member]	Dec. 31, 2011 Kaplan Restricted Stock [Member] Senior Manager [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Right to elect Board of Directors percentage																							30.00%
Conversion of Class A shares to Class B																					11,500	50,810
Conversion of stock from Class A to Class B, percentage																					1.00%	4.00%
Shares repurchased by company																							644,948	1,057,940	145,040
Cost of shares repurchased by company		$ 248,055,000	$ 404,816,000	$ 60,956,000																			$ 248,100,000	$ 404,800,000	$ 61,000,000
Number of shares authorized to be repurchased																										750,000
Number of shares authorized to be repurchased remaining under previous authorization																							43,573
Authorized shares remaining																							493,474
Shares reserved for issuance										362,525				316,805
Shares subject to award outstanding		77,319	48,359	66,020	32,785									77,319
Shares available for future awards										233,481				239,486
Share awards outstanding, restriction will lapse in 2012														3,200
Share awards outstanding, restriction will lapse in 2013														31,555
Share awards outstanding, restriction will lapse in 2014														674
Share awards outstanding, restriction will lapse in 2015														41,890
Awarded, Number of Shares		44,030	1,859	48,440
Stock-based Compensation Expense						(1,300,000)	(1,200,000)	900,000		2,700,000	1,400,000	1,300,000		5,300,000	2,900,000	4,600,000
Total unrecognized compensation expense										7,500,000				18,700,000
Years over which cost expected to be recognized										1.9				1.8
Shares reserved for options granted under the plan																											1,900,000
Option vesting, period										four years							four to five years											three-year period
Option Vesting Period, Maximum										ten years
Shares subject to stock options outstanding		129,044	87,919	90,569	87,025					129,044							0
Options outstanding exercisable now										45,585
Options outstanding exercisable in 2012										27,886
Options outstanding exercisable in 2013										24,448
Options outstanding exercisable in 2014										18,375
Options outstanding exercisable in 2015										12,750
Intrinsic value of options outstanding										100,000
Intrinsic value of options exercisable										100,000
Intrinsic value of options unvested										100,000
Market value of company's stock		$ 376.81
Options unvested, shares										83,459	47,845
Options unvested, average exercise price										$ 463.528327152691	$ 407.68
Options unvested, weighted average remaining contractual term, years										9.4
Options Outstanding, Weighted Average Remaining Contractual Life (yrs.)		8.2
Options Outstanding, Weighted Average Exercise Price		$ 494.95	$ 495.05	$ 525.44	$ 581.17
Intrinsic value of options exercised																	1,000,000
Granted, Number of Shares	26,675	51,000	22,500	24,294					1,000				50,000				0	0	0
Weighted average fair value, granted options										$ 110.67	$ 106.7	$ 108.92
Exercised, Number of Shares										0		0						0	0	2,000
Common Stock, shares outstanding																														3,750
Restricted stock issued																													3,456
Fair value of company common stock																												$ 1,165
Accrual balance related to stock based compensation						8,100,000
Stock compensation payouts						$ 0	$ 0	$ 0
Antidilutive securities, shares		115,294	30,225	74,569
Dividends declared per common share		$ 9.40	$ 9.00	$ 8.60