Consolidated Statement of Changes in Shareholders' Equity - 6 months ended Jun. 30, 2015 - USD ($) $ in Thousands	Total	Common stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Accumulated other comprehensive income [Member]	Treasury stock [Member]
Balance at Dec. 31, 2014	$ 3,903,351	$ 126,472	$ 1,113,551	$ 3,441,424	$ 175,014	$ (953,110)
Net earnings	193,334			193,334
Other comprehensive income	(64,302)				(64,302)
Stock-based compensation	10,947	402	10,545
Issuance of 60 shares for exercise of options, including tax effect	4,744	60	4,684
Issuance of 49 shares for employee stock purchase plan	2,024	49	1,975
Surrender of 146 shares of restricted stock for employee's tax liability	(7,964)	(146)	(7,818)
Purchase of 1,241 common shares	(69,569)					(69,569)
Cash dividends declared, $0.59 per share	(56,443)			(56,443)
Balance at Jun. 30, 2015	$ 3,916,122	$ 126,837	$ 1,122,937	$ 3,578,315	$ 110,712	$ (1,022,679)