Employee Compensation Plans - Schedule of Stock Compensation Assumptions Used (Details)	Dec. 31, 2017 USD ($)
January Fourteen Two Thousand Thirteen [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	13 days
Share Based Compensation Arrangement By Cash Payment Award Stock Appreciation Rights Fair Value Assumptions Expected Volatility Rate	20.683%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Risk Free Interest Rate	0.613%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Expected Dividend Payments	$ 0
January Six Two Thousand Seventeen [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	4 years
Share Based Compensation Arrangement By Cash Payment Award Stock Appreciation Rights Fair Value Assumptions Expected Volatility Rate	34.439%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Risk Free Interest Rate	2.089%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Expected Dividend Payments	$ 0
January Six Two Thousand Sixteen [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	3 years
Share Based Compensation Arrangement By Cash Payment Award Stock Appreciation Rights Fair Value Assumptions Expected Volatility Rate	35.174%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Risk Free Interest Rate	1.971%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Expected Dividend Payments	$ 0
January Nine Two Thousand Fifteen [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	2 years
Share Based Compensation Arrangement By Cash Payment Award Stock Appreciation Rights Fair Value Assumptions Expected Volatility Rate	32.249%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Risk Free Interest Rate	1.887%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Expected Dividend Payments	$ 0
January Fourteen Two Thousand Fourteen [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	1 year
Share Based Compensation Arrangement By Cash Payment Award Stock Appreciation Rights Fair Value Assumptions Expected Volatility Rate	27.995%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Risk Free Interest Rate	1.738%
Share-based Compensation Arrangement by Cash Payment Award Stock Appreciation Rights, Fair Value Assumptions, Expected Dividend Payments	$ 0