Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 15,610	$ 14,372
Short-term finance receivables allowance	11,921	13,232
Long-term finance receivables allowance	$ 5,999	$ 7,177
Preferred stock par value (in dollars per share)	$ 50	$ 50
Preferred stock dividend rate	4.00%	4.00%
Preference stock, par value (in dollars per share)	$ 0	$ 0
Preference stock dividend rate (in dollars per share)	2.12	2.12
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	480,000,000	480,000,000
Common stock, shares issued (in shares)	323,337,912	323,337,912
Treasury stock (in shares)	136,777,086	137,669,194