Other Comprehensive Earnings (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Equity [Abstract]
Foreign currency translation adjustments, before-tax amount	$ 6,037	$ (5,588)	$ 1,898	$ (9,834)
Foreign currency translation adjustments, tax	1,908	(1,638)	177	(2,632)
Foreign currency translation adjustments, net-of-tax amount	4,129	(3,950)	1,721	(7,202)
Change in unrealized gains on investments, before-tax amount	5,702	(14,466)	12,103	(12,832)
Change in unrealized gains on investments, tax	1,996	(5,064)	4,236	(4,492)
Change in unrealized gains on investments, net-of-tax amount	3,706	(9,402)	7,867	(8,340)
Less: reclassification adjustment for gains included in net earnings, before-tax amount	(96)	(1,509)	(298)	(1,901)
Less: reclassification adjustment for gains included in net earnings, tax	(34)	(528)	(105)	(665)
Less: reclassification adjustment for gains included in net earnings, net-of-tax amount	(62)	(981)	(193)	(1,236)
Net unrealized gains, before-tax amount	5,606	(15,975)	11,805	(14,733)
Net unrealized gains, tax	1,962	(5,592)	4,131	(5,157)
Net unrealized gains, net-of-tax amount	3,644	(10,383)	7,674	(9,576)
Other comprehensive earnings (loss), before taxes	11,643	(21,563)	13,703	(24,567)
Other comprehensive earnings (loss), tax	3,870	(7,230)	4,308	(7,789)
Other comprehensive earnings (loss), net-of-tax amount	$ 7,773	$ (14,333)	$ 9,395	$ (16,778)