Schedule I - Condensed Financial Information of Registrant (Condensed Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current Assets:
Cash and cash equivalents	$ 433,155	$ 340,110	$ 230,253	$ 350,138
Available for sale securities	1,567,020	1,812,512
Other assets	132,683	130,796
Deferred taxes	94,060	51,086
Total current assets	2,919,890	3,049,964
Property and equipment, net	201,395	183,793
Goodwill	565,886	565,886	605,900
Other intangible assets, net	13,842	17,271
Deferred taxes	5,793	13,583
Other assets	162,551	103,893
Total Assets	3,929,125	3,934,390
Current Liabilities:
Other current liabilities	72,098	75,649
Total current liabilities	1,577,178	1,638,096
Other noncurrent liabilities	213,427	240,169
Total Liabilities	2,300,314	2,377,360
Commitments and contingencies
Stockholders’ Equity:
Common stock	150	149
Additional paid-in capital	1,377,624	1,329,000
Treasury common stock, at cost	(2,179,744)	(2,092,625)
Retained earnings	2,463,648	2,293,522
Accumulated other comprehensive income	(32,867)	26,984	16,600	500
Total Stockholders' Equity	1,628,811	1,557,030	1,443,146	1,694,416
Total Liabilities and Stockholders' Equity	3,929,125	3,934,390
Parent Company [Member]
Current Assets:
Cash and cash equivalents	131,350	105,809	87,948	203,804
Available for sale securities	78,242	0
Other assets	30,965	36,351
Deferred taxes	16,158	0
Due from subsidiaries	177,957	169,853
Total current assets	434,672	312,013
Property and equipment, net	162,679	145,821
Goodwill	319,732	319,732
Other intangible assets, net	1,198	1,823
Investment in subsidiaries	2,608,631	2,648,148
Deferred taxes	6,523	17,823
Other assets	71,661	66,857
Total Assets	3,605,096	3,512,217
Current Liabilities:
Due to subsidiaries	237,555	223,612
Deferred taxes	0	18,807
Other current liabilities	100,755	96,162
Total current liabilities	338,310	338,581
Intercompany Notes Payable, long term	977,233	987,746
Long term debt	499,300	499,095
Other noncurrent liabilities	161,442	129,765
Total Liabilities	1,976,285	1,955,187
Commitments and contingencies
Stockholders’ Equity:
Common stock	150	149
Additional paid-in capital	1,377,624	1,329,000
Treasury common stock, at cost	(2,179,744)	(2,092,625)
Retained earnings	2,463,648	2,293,522
Accumulated other comprehensive income	(32,867)	26,984
Total Stockholders' Equity	1,628,811	1,557,030
Total Liabilities and Stockholders' Equity	$ 3,605,096	$ 3,512,217