Capital Stock, Stock Awards, and Stock Options (Narrative) (Details) (USD $)	12 Months Ended				12 Months Ended							1 Months Ended	12 Months Ended						2 Months Ended	12 Months Ended				2 Months Ended	12 Months Ended
	Dec. 31, 2012 year	Dec. 31, 2011	Jan. 02, 2011	Jan. 03, 2010	Dec. 31, 2012 Accelerated dividends in lieu of regular quarterly dividends in 2013 [Member]	Dec. 31, 2012 Education [Member]	Dec. 31, 2011 Education [Member]	Dec. 31, 2010 Education [Member]	Dec. 31, 2012 Kaplan Stock Option [Member]	Dec. 31, 2011 Kaplan Stock Option [Member]	Dec. 31, 2010 Kaplan Stock Option [Member]	Dec. 31, 2011 Kaplan Stock Option [Member] Senior Manager [Member]	Dec. 31, 2012 Class A Common Stock [Member]	Dec. 31, 2011 Class A Common Stock [Member]	Dec. 31, 2012 Class B Common Stock [Member]	Dec. 31, 2011 Class B Common Stock [Member]	Jan. 02, 2011 Class B Common Stock [Member]	Sep. 30, 2011 Class B Common Stock [Member]	Feb. 28, 2013 Class B Common Stock [Member] Stock Option Plan [Member]	Dec. 31, 2012 Class B Common Stock [Member] Stock Option Plan [Member] year	Dec. 31, 2011 Class B Common Stock [Member] Stock Option Plan [Member]	Jan. 02, 2011 Class B Common Stock [Member] Stock Option Plan [Member]	Dec. 31, 2011 Class B Common Stock [Member] Stock Option Plan [Member] Exercise price above fair market value of common stock [Member]	Feb. 28, 2013 Class B Common Stock [Member] Stock Awards [Member]	Dec. 31, 2012 Class B Common Stock [Member] Stock Awards [Member] year	Dec. 31, 2011 Class B Common Stock [Member] Stock Awards [Member]	Jan. 02, 2011 Class B Common Stock [Member] Stock Awards [Member]	Dec. 31, 2012 Kaplan Restricted Stock [Member]	Dec. 31, 2012 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													10,000	11,500
Conversion of stock from Class A to Class B, percentage													1.00%	1.00%
Shares repurchased by company															301,231	644,948	1,057,940
Cost of shares repurchased by company	$ 103,196,000	$ 248,055,000	$ 404,816,000												$ 103,200,000	$ 248,100,000	$ 404,800,000
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 for repurchase															192,243
Shares reserved for issuance																				351,675					302,055
Shares subject to award outstanding	207,917	77,319	48,359	66,020																					207,917				759
Shares available for future awards																				225,981					94,138
Share awards outstanding, restriction will lapse in 2013																									28,555
Share awards outstanding, restriction will lapse in 2014																									2,674
Share awards outstanding, restriction will lapse in 2015																									41,968
Share awards outstanding, restriction will lapse in 2016																									24,850
Share awards outstanding, restriction will lapse in 2017																									67,370
Share awards outstanding, restriction will lapse in 2018																									42,500
Awarded, Number of Shares	145,348	44,030	1,859																					7,681
Stock-based Compensation Expense						(1,100,000)	(1,300,000)	(1,200,000)												2,900,000	2,700,000	1,400,000			11,400,000	8,900,000	4,800,000
Total unrecognized compensation expense																				5,100,000					50,900,000
Years over which cost expected to be recognized																				2.3					2.3
Shares reserved for options granted under the plan																				1,900,000
Vesting period									generally four to five years											four years								three-year period
Option Vesting Period, Maximum																				10 years
Shares subject to stock options outstanding	125,694	129,044	87,919	90,569					0											125,694
Options outstanding exercisable now																				64,021
Options outstanding exercisable in 2013																				25,423
Options outstanding exercisable in 2014																				19,750
Options outstanding exercisable in 2015																				14,625
Options outstanding exercisable in 2016																				1,875
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	$ 365.21
Options unvested, shares																				61,673	83,459
Options unvested, average exercise price																				$ 460.24	$ 463.53
Options unvested, weighted average remaining contractual term, years																				8.2
Options Outstanding, Weighted Average Remaining Contractual Life	7.2
Options Outstanding, Weighted Average Exercise Price	$ 478.32	$ 494.95	$ 495.05	$ 525.44
Intrinsic value of options exercised										1,000,000
Granted, Number of Shares	7,500	51,000	22,500						0	0	0								15,000				50,000
Weighted average fair value, granted options																				$ 91.71	$ 110.67	$ 106.70
Exercised, Number of Shares									0		0	2,000								0	0	0
Exercised, Average Option Price												$ 652
Common Stock, shares outstanding													1,219,383	1,229,383	6,208,118	6,361,617													6,447
Fair value of company common stock																												$ 973
Accrual balance related to stock based compensation						7,000,000
Stock compensation payouts						$ 0	$ 0	$ 0
Antidilutive securities, shares																				124,694	115,294	30,225
Dividends declared per common share	$ 9.80	$ 9.40	$ 9.00		$ 9.80