Income Taxes (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
Income Tax Examination, Range of Possible Losses	$ 14,000,000								$ 14,000,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense									900,000	(100,000)	1,200,000
Operating Loss Carryforwards	19,200,000								19,200,000
Current Federal Tax Expense (Benefit)									44,112,000	42,934,000	43,632,000
Current Foreign Tax Expense (Benefit)									25,103,000	20,965,000	11,515,000
Current State and Local Tax Expense (Benefit)									4,903,000	4,344,000	5,600,000
Current Income Tax Expense (Benefit)									74,118,000	68,243,000	60,747,000
Deferred Federal Income Tax Expense (Benefit)									4,754,000	963,000	(8,905,000)
Deferred Foreign Income Tax Expense (Benefit)									1,884,000	2,677,000	2,892,000
Deferred State and Local Income Tax Expense (Benefit)									152,000	(35,000)	(536,000)
Deferred Income Tax Expense (Benefit)									6,790,000	3,605,000	(6,549,000)
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