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Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
	May 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		$ 54,314		$ 54,314
Total intrinsic value of options exercised				111,031
Aggregate intrinsic value of options exercisable		$ 271,157		$ 271,157
Market value of Company's common stock		$ 62.52		$ 62.52
Weighted average exercise price per share		$ 29.36		$ 29.36
Total options outstanding		14,399		14,399
Total options exercisable		8,178		8,178
Cash dividend declared (in USD per share)	$ 0.30	$ 0.30	$ 0.28	$ 0.30	$ 0.28
Cash dividends declared				$ 47,139	$ 44,264
Common Stock Buyback
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased and retired				2,751
Company purchased, cost				$ 186,900
Remaining stock repurchase authorization amount		$ 183,738		$ 183,738
2014 Plan \| Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rate				50.00%
2014 Plan \| Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rate				50.00%