New accounting pronouncements (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) for impact of new accounting pronouncement			$ (6,771)		$ 1,721	$ 0
Right of Use Asset-Operating Leases		$ 298,393
Lease liability		308,040
Reduction to deferred tax liabilities		$ (76,206)		$ (64,273)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of Use Asset-Operating Leases			336,083
Lease liability			344,362
Reduction to deferred tax liabilities			1,508
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) for impact of new accounting pronouncement			(6,771)		$ 1,897	$ 72,921
Retained Earnings | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) for impact of new accounting pronouncement			$ 6,771
Subsequent event | Retained Earnings | ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) for impact of new accounting pronouncement	$ 200