Summary of Significant Accounting Policies - New Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2018	Jun. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements
Operating lease liabilities				$ 520,593
Operating lease maturity payments
2019				3,651,178
2020				3,392,090
2021				3,031,609
2022				2,638,397
2023				2,176,031
Thereafter				5,817,996
Total				$ 20,707,301
Minimum
New Accounting Pronouncements
Discount rate				3.97%
Maximum
New Accounting Pronouncements
Discount rate				5.52%
Accounting Standards Update 2016-02 | Restatement Adjustment
New Accounting Pronouncements
Right-of use assets for operating leases					$ 524,000
Operating lease liabilities					$ 524,000
Accounting Standards Update 2016-02 | Proforma Adjustment
New Accounting Pronouncements
Lease expenses	$ 11,000	$ 22,300	$ 45,000