Supplementary Balance Sheet Information - Significant Components of Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Deferred revenues	$ 40,261	$ 39,863
Accrued expenses	29,429	26,017
Accrued third-party commissions	25,793	9,810
Dividends payable	19,351	19,367
Accrued interest	11,325	2,820
Other	102,387	68,702
Total	$ 228,546	$ 166,579