Other Intangible Assets (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Other intangible assets
Cost	$ 709,977,000		$ 710,092,000
Accumulated Amortization	(383,845,000)		(362,596,000)
Carrying Amount	326,132,000		347,496,000
Total amortization expense	22,000,000	23,000,000
Customer relationships
Other intangible assets
Cost	293,932,000		293,932,000
Accumulated Amortization	(123,590,000)		(113,906,000)
Carrying Amount	170,342,000		180,026,000
Weighted Average Useful life	8 years
Contract-based
Other intangible assets
Cost	255,366,000		255,366,000
Accumulated Amortization	(184,813,000)		(178,138,000)
Carrying Amount	70,553,000		77,228,000
Weighted Average Useful life	10 years
Technology-based
Other intangible assets
Cost	126,272,000		126,387,000
Accumulated Amortization	(70,562,000)		(66,338,000)
Carrying Amount	55,710,000		60,049,000
Weighted Average Useful life	7 years
Trademark portfolio
Other intangible assets
Cost	29,700,000		29,700,000
Accumulated Amortization	(2,723,000)		(2,351,000)
Carrying Amount	26,977,000		27,349,000
Weighted Average Useful life	20 years
Favorable leases
Other intangible assets
Cost	4,707,000		4,707,000
Accumulated Amortization	(2,157,000)		(1,863,000)
Carrying Amount	$ 2,550,000		$ 2,844,000
Weighted Average Useful life	4 years