Goodwill and Identifiable Intangible Assets - Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment and intangible asset impairment	$ 0
Goodwill
Balance at the beginning of the period	852,700,000	$ 845,500,000
2018 acquisitions		13,400,000
Adjustment of purchase price allocations		2,300,000
Foreign currency translation of non-USD functional currency subsidiary goodwill	4,300,000	(8,400,000)
Adjustment for sale of business	(13,300,000)
Balance at the end of the period	843,700,000	852,700,000
Aviation segment
Goodwill
Balance at the beginning of the period	322,900,000	326,900,000
2018 acquisitions		0
Adjustment of purchase price allocations		(2,200,000)
Foreign currency translation of non-USD functional currency subsidiary goodwill	700,000	(1,800,000)
Adjustment for sale of business	0
Balance at the end of the period	323,600,000	322,900,000
Land segment
Goodwill
Balance at the beginning of the period	529,700,000	518,500,000
2018 acquisitions		13,400,000
Adjustment of purchase price allocations		4,500,000
Foreign currency translation of non-USD functional currency subsidiary goodwill	3,600,000	(6,700,000)
Adjustment for sale of business	(13,300,000)
Balance at the end of the period	520,100,000	$ 529,700,000
Land segment | Land
Goodwill
Balance at the end of the period	$ 455,500,000