Quarterly report pursuant to Section 13 or 15(d)

Debt, Net (Details 2)

v3.5.0.2
Debt, Net (Details 2) - USD ($)
$ in Thousands
Jun. 30, 2016
Dec. 31, 2015
Carrying amount and estimated fair value of debt    
Carrying Value $ 2,094,486 $ 2,077,752
Carrying Amount    
Carrying amount and estimated fair value of debt    
Variable-rate debt 588,116 609,194
Carrying Value 2,094,486 2,077,752
Carrying Amount | Unsecured senior notes    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 1,186,672 1,185,842
Carrying Amount | Other fixed-rate debt    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 319,698 282,716
Total Estimated Fair Value    
Carrying amount and estimated fair value of debt    
Variable-rate debt 592,032 610,987
Carrying Value 2,148,333 2,114,636
Total Estimated Fair Value | Unsecured senior notes    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 1,227,235 1,211,658
Total Estimated Fair Value | Other fixed-rate debt    
Carrying amount and estimated fair value of debt    
Fixed-rate debt $ 329,066 $ 291,991