Income Taxes Income tax expense, income tax reconciliation (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate									25.00%	25.00%	25.00%
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate									$ 81,026,000	$ 72,115,000	$ 59,711,000
Income Tax Reconciliation, Foreign Income Tax Rate Differential									(6,698,000)	(864,000)	(241,000)
Income Tax Reconciliation, Nondeductible Expense									2,138,000	917,000	2,691,000
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance									(1,156,000)	(2,099,000)	(1,279,000)
Income Tax Reconciliation, State and Local Income Taxes									3,439,000	2,895,000	3,166,000
Income Tax Reconciliation, Prior Year Income Taxes									(4,258,000)	1,038,000	(17,229,000)
Income Tax Reconciliation, Other Adjustments									59,000	(4,374,000)	7,050,000
Income Tax Reconciliation, Other Reconciling Items									6,358,000	2,220,000	329,000
Income Tax Expense (Benefit)	20,718,000	20,490,000	19,664,000	20,036,000	18,394,000	18,671,000	16,997,000	17,786,000	80,908,000	71,848,000	54,198,000
Income Tax Reconciliation, Tax Settlements											$ 10,400,000