Other comprehensive income (loss) (Tables)

12 Months Ended

Dec. 31, 2014

Statement Of Income And Comprehensive Income [Abstract]

Changes in Accumulated Other Comprehensive Income (Loss)

Charges and credits to other comprehensive income (loss) have been as follows:

	Interest rate swap and cap agreements			Investment securities			Foreign currency translation adjustments			Accumulated other comprehensive income (loss)
Balance at December 31, 2011	$	(19,328	)	$	(156	)	$	—		$	(19,484	)
Unrealized (losses) gains		(10,154	)		2,524			(1,205	)		(8,835	)
Related income tax		3,950			(983	)		—			2,967
		(6,204	)		1,541			(1,205	)		(5,868	)
Reclassification from accumulated other    comprehensive losses (income) into net income		16,578			(123	)		—			16,455
Related income tax		(6,448	)		48			—			(6,400	)
		10,130			(75	)		—			10,055
Balance at December 31, 2012	$	(15,402	)	$	1,310		$	(1,205	)	$	(15,297	)
Unrealized gains (losses)		277			3,752			(2,216	)		1,813
Related income tax		(108	)		(1,452	)		—			(1,560	)
		169			2,300			(2,216	)		253
Reclassification from accumulated other    comprehensive losses (income) into net income		21,096			(802	)		—			20,294
Related income tax		(8,207	)		312			—			(7,895	)
		12,889			(490	)		—			12,399
Balance at December 31, 2013	$	(2,344	)	$	3,120		$	(3,421	)	$	(2,645	)
Unrealized (losses) gains		(16,509	)		425			(22,952	)		(39,036	)
Related income tax		6,450			(187	)		—			6,263
		(10,059	)		238			(22,952	)		(32,773	)
Reclassification from accumulated other    comprehensive losses (income) into net income		17,409			(340	)		—			17,069
Related income tax		(6,801	)		133			—			(6,668	)
		10,608			(207	)		—			10,401
Balance at December 31, 2014	$	(1,795	)	$	3,151		$	(26,373	)	$	(25,017	)