Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-Term Debt
Debt, Long-term and short-term, excluding financing costs	$ 9,574,650	$ 8,667,055
Less: unamortized debt issuance costs	(187,214)	(139,812)
Total debt, net of unamortized debt issuance costs	9,387,436	8,527,243
Less: current portion	(1,285,735)	(899,542)
Long-term portion	8,101,701	7,627,701
$1.4 billion unsecured revolving credit facility, LIBOR plus 1.50%, currently 2.26% and a facility fee of 0.25%, due 2020
Long-Term Debt
Long-term debt	925,000	945,000
$1.2 billion unsecured revolving credit facility, LIBOR plus 1.50%, currently 2.24% and a facility fee of 0.25%, due 2018
Long-Term Debt
Long-term debt	805,000	895,000
Unsecured senior notes and senior debentures, 5.25% to 7.50%, due 2018, 2022 and 2027
Long-Term Debt
Long-term debt	1,073,261	1,434,542
$200 million unsecured term loan, LIBOR plus 1.30%, currently 2.06% due 2017
Long-Term Debt
Long-term debt	200,000	0
$841.8 million unsecured term loan, LIBOR plus 1.00%, currently 2.26% due through 2028
Long-Term Debt
Long-term debt	806,756	0
$226.1 million unsecured term loan, 2.53%, due through 2028
Long-Term Debt
Long-term debt	216,677	0
€700.7 million unsecured term loan, EURIBOR plus 1.15% currently 1.15%, due through 2028
Long-Term Debt
Long-term debt	708,417	0
$742.1 million unsecured term loan, LIBOR plus 1.30%, currently 2.56%, due through 2027
Long-Term Debt
Long-term debt	649,338	711,180
$273.2 million unsecured term loan, LIBOR plus 1.75%, currently 2.52%, due 2017
Long-Term Debt
Long-term debt	273,166	0
$519 million unsecured term loan, LIBOR plus 0.45%, currently 1.71%, due through 2020
Long-Term Debt
Long-term debt	173,049	216,311
$420 million unsecured term loan, 5.41%, due through 2021
Long-Term Debt
Long-term debt	171,444	207,223
$420 million unsecured term loan, LIBOR plus 1.65%, currently 2.91%, due through 2021
Long-Term Debt
Long-term debt	175,000	210,000
€159.4 million unsecured term loan, EURIBOR plus 1.58%, currently 1.58%, due through 2021
Long-Term Debt
Long-term debt	70,082	86,650
$524.5 million unsecured term loan, LIBOR plus 0.50%, currently 1.48%, due through 2021
Long-Term Debt
Long-term debt	218,542	262,250
$566.1 million unsecured term loan, LIBOR plus 0.37%, currently 1.63%, due through 2022
Long-Term Debt
Long-term debt	259,448	306,621
$1.1 billion unsecured term loan, LIBOR plus 1.65%, currently 2.91%, due through 2022
Long-Term Debt
Long-term debt	460,652	537,426
$632.0 million unsecured term loan, LIBOR plus 0.40%, currently 1.38%, due through 2023
Long-Term Debt
Long-term debt	368,643	421,306
$673.5 million unsecured term loan, LIBOR plus 0.40%, currently 1.66%, due through 2024
Long-Term Debt
Long-term debt	448,983	505,106
$65.0 million unsecured term loan, LIBOR plus 1.75%, currently 2.52%, due through 2019
Long-Term Debt
Long-term debt	67,027	71,500
$380.0 million unsecured term loan, LIBOR plus 1.75%, currently 2.52%, due 2018
Long-Term Debt
Long-term debt	380,000	380,000
$791.1 million unsecured term loan, LIBOR plus 1.30%, currently 2.56%, due through 2026
Long-Term Debt
Long-term debt	659,256	725,182
$290.0 million unsecured term loan, LIBOR plus 1.75%, currently 2.52%, due 2018
Long-Term Debt
Long-term debt	290,000	290,000
€365 million unsecured term loan, EURIBOR plus 1.75%, currently 1.75%, due 2017
Long-Term Debt
Long-term debt	123,963	396,755
$7.3 million unsecured term loan, LIBOR plus 2.5%, currently 3.76%, due through 2023
Long-Term Debt
Long-term debt	3,964	4,440
$30.3 million unsecured term loan, LIBOR plus 3.75%, currently 4.70%, due through 2021
Long-Term Debt
Long-term debt	6,597	11,793
Capital lease obligations
Long-Term Debt
Capital lease obligations	$ 40,385	$ 48,770