Summary of Significant Accounting Policies - Stock Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Stock compensation expense	$ 5,367	$ 4,184	$ 3,506
Capitalized stock compensation	408	604	485
Stock compensation expense, net	4,959	3,580	3,021
Excess tax benefits, net of deficiencies	$ 1,523	$ 3,314	$ 1,709

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Amount of capitalized and expensed compensation cost from equity-based compensation arrangements.

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