Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Reconciliation of the Numerators and Denominators Used in the Basic and Diluted Per-Share Computations

A reconciliation of the numerators and denominators used in the basic and diluted per-share computations is presented as follows for each class of common stock:

(dollars in thousands, except per share data)						For the years ended December 31,
	2018					2017					2016
	Allocated net income (numerator)		Weighted shares (denominator)	Per- share amount		Allocated net income (numerator)		Weighted shares (denominator)	Per- share amount		Allocated net income (numerator)		Weighted shares (denominator)	Per- share amount
Class A – Basic EPS:
Income available to  Class A stockholders	$	285,864	46,188,637	$	6.19	$	195,386	46,186,831	$	4.23	$	208,644	46,188,952	$	4.52
Dilutive effect of stock-based awards	0		25,776	—		0		49,832	—		0		145,551	—
Assumed conversion of Class B shares	2,360		6,100,800	—		1,613		6,100,800	—		1,722		6,100,800	—
Class A – Diluted EPS:
Income available to Class A stockholders on Class A equivalent shares	$	288,224	52,315,213	$	5.51	$	196,999	52,337,463	$	3.76	$	210,366	52,435,303	$	4.01
Class B – Basic EPS:
Income available to Class B stockholders	$	2,360	2,542	$	928	$	1,613	2,542	$	635	$	1,722	2,542	$	678
Class B – Diluted EPS:
Income available to Class B stockholders	$	2,359	2,542	$	928	$	1,613	2,542	$	634	$	1,721	2,542	$	677