Earnings Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator
Net income	$ 164,965	$ 113,977	$ 117,910	$ 101,652	$ 91,817	$ 49,764	$ 38,450	$ 26,126	$ 498,504	$ 206,157	$ 112,994
Denominator
Weighted average common shares outstanding - basic									33,706,782	33,312,554	30,886,382
Dilutive effect of restricted stock units									738,136	297,544	300,570
Weighted average common shares outstanding - diluted									34,444,918	33,610,098	31,186,952
Earnings per share:
Basic	$ 4.89	$ 3.38	$ 3.49	$ 3.03	$ 2.75	$ 1.49	$ 1.15	$ 0.79	$ 14.79	$ 6.19	$ 3.66
Diluted	$ 4.78	$ 3.31	$ 3.47	$ 3.00	$ 2.72	$ 1.48	$ 1.15	$ 0.78	$ 14.47	$ 6.13	$ 3.62